diff --git a/has-arrow-function-support/README.md b/has-arrow-function-support/README.md
new file mode 100644
index 00000000..e3f2e506
--- /dev/null
+++ b/has-arrow-function-support/README.md
@@ -0,0 +1,125 @@
+
+
+# Arrow Function Support
+
+> Detect native [`arrow function`][arrow-function] support.
+
+
+
+## Usage
+
+```javascript
+var hasArrowFunctionSupport = require( '@stdlib/assert/has-arrow-function-support' );
+```
+
+#### hasArrowFunctionSupport()
+
+Detects if a runtime environment supports ES2015 [`arrow functions`][arrow-function]` such as `( a, b ) => a + b`, `x => x`, or `( x ) => { return x*x; }`.
+
+```javascript
+var bool = hasArrowFunctionSupport();
+// returns
+```
+
+
+
+
+
+
+
+## Notes
+
+- The implementation uses code evaluation, which may be problematic in browser contexts enforcing a strict [content security policy][mdn-csp] (CSP).
+
+
+
+
+
+
+
+## Examples
+
+
+
+```javascript
+var hasArrowFunctionSupport = require( '@stdlib/assert/has-arrow-function-support' );
+
+var bool = hasArrowFunctionSupport();
+if ( bool ) {
+ console.log( 'Environment has native arrow function support.' );
+} else {
+ console.log( 'Environment lacks native arrow function support.' );
+}
+```
+
+
+
+
+
+* * *
+
+
+
+## CLI
+
+
+
+### Usage
+
+```text
+Usage: has-arrow-function-support [options]
+
+Options:
+
+ -h, --help Print this message.
+ -V, --version Print the package version.
+```
+
+
+
+
+
+
+
+### Examples
+
+```bash
+$ has-arrow-function-support
+
+```
+
+
+
+
+
+
+
+
+
+
+
+[arrow-function]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions
+
+[mdn-csp]: https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP
+
+
+
+
diff --git a/has-arrow-function-support/benchmark/benchmark.js b/has-arrow-function-support/benchmark/benchmark.js
new file mode 100644
index 00000000..078604e5
--- /dev/null
+++ b/has-arrow-function-support/benchmark/benchmark.js
@@ -0,0 +1,50 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var bench = require( '@stdlib/bench' );
+var isBoolean = require( './../../is-boolean' ).isPrimitive;
+var pkg = require( './../package.json' ).name;
+var hasArrowFunctionSupport = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+ var bool;
+ var i;
+
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ // Note: the following *could* be optimized away via loop-invariant code motion. If so, the entire loop will disappear.
+ bool = hasArrowFunctionSupport();
+ if ( !isBoolean( bool ) ) {
+ b.fail( 'should return a boolean' );
+ }
+ }
+ b.toc();
+ if ( isBoolean( bool ) ) {
+ b.pass( 'benchmark finished' );
+ } else {
+ b.fail( 'should return a boolean' );
+ }
+ b.end();
+});
diff --git a/has-arrow-function-support/bin/cli b/has-arrow-function-support/bin/cli
new file mode 100755
index 00000000..f92ab0b6
--- /dev/null
+++ b/has-arrow-function-support/bin/cli
@@ -0,0 +1,60 @@
+#!/usr/bin/env node
+
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var resolve = require( 'path' ).resolve;
+var readFileSync = require( '@stdlib/fs/read-file' ).sync;
+var CLI = require( '@stdlib/cli/ctor' );
+var detect = require( './../lib' );
+
+
+// MAIN //
+
+/**
+* Main execution sequence.
+*
+* @private
+*/
+function main() {
+ var flags;
+ var cli;
+
+ // Create a command-line interface:
+ cli = new CLI({
+ 'pkg': require( './../package.json' ),
+ 'options': require( './../etc/cli_opts.json' ),
+ 'help': readFileSync( resolve( __dirname, '..', 'docs', 'usage.txt' ), {
+ 'encoding': 'utf8'
+ })
+ });
+
+ // Get any provided command-line options:
+ flags = cli.flags();
+ if ( flags.help || flags.version ) {
+ return;
+ }
+
+ console.log( detect() ); // eslint-disable-line no-console
+}
+
+main();
diff --git a/has-arrow-function-support/docs/repl.txt b/has-arrow-function-support/docs/repl.txt
new file mode 100644
index 00000000..47cc8de6
--- /dev/null
+++ b/has-arrow-function-support/docs/repl.txt
@@ -0,0 +1,17 @@
+
+{{alias}}()
+ Tests whether an environment supports native arrow functions.
+
+ Returns
+ -------
+ bool: boolean
+ Boolean indicating if an environment support arrow functions.
+
+ Examples
+ --------
+ > var bool = {{alias}}()
+
+
+ See Also
+ --------
+
diff --git a/has-arrow-function-support/docs/types/index.d.ts b/has-arrow-function-support/docs/types/index.d.ts
new file mode 100644
index 00000000..a70ce9f9
--- /dev/null
+++ b/has-arrow-function-support/docs/types/index.d.ts
@@ -0,0 +1,35 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+// TypeScript Version: 2.0
+
+/**
+* Tests for native arrow function support.
+*
+* @returns boolean indicating if an environment has native arrow function support
+*
+* @example
+* var bool = hasArrowFunctionSupport();
+* // returns
+*/
+declare function hasArrowFunctionSupport(): boolean;
+
+
+// EXPORTS //
+
+export = hasArrowFunctionSupport;
diff --git a/has-arrow-function-support/docs/types/test.ts b/has-arrow-function-support/docs/types/test.ts
new file mode 100644
index 00000000..44f4b6ef
--- /dev/null
+++ b/has-arrow-function-support/docs/types/test.ts
@@ -0,0 +1,33 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+import hasArrowFunctionSupport = require( './index' );
+
+
+// TESTS //
+
+// The function returns a boolean...
+{
+ hasArrowFunctionSupport(); // $ExpectType boolean
+}
+
+// The compiler throws an error if the function is provided arguments...
+{
+ hasArrowFunctionSupport( true ); // $ExpectError
+ hasArrowFunctionSupport( [], 123 ); // $ExpectError
+}
diff --git a/has-arrow-function-support/docs/usage.txt b/has-arrow-function-support/docs/usage.txt
new file mode 100644
index 00000000..1be9f117
--- /dev/null
+++ b/has-arrow-function-support/docs/usage.txt
@@ -0,0 +1,7 @@
+
+Usage: has-arrow-function-support [options]
+
+Options:
+
+ -h, --help Print this message.
+ -V, --version Print the package version.
diff --git a/has-arrow-function-support/etc/cli_opts.json b/has-arrow-function-support/etc/cli_opts.json
new file mode 100644
index 00000000..f245a17e
--- /dev/null
+++ b/has-arrow-function-support/etc/cli_opts.json
@@ -0,0 +1,14 @@
+{
+ "boolean": [
+ "help",
+ "version"
+ ],
+ "alias": {
+ "help": [
+ "h"
+ ],
+ "version": [
+ "V"
+ ]
+ }
+}
diff --git a/has-arrow-function-support/examples/index.js b/has-arrow-function-support/examples/index.js
new file mode 100644
index 00000000..a4ab2fc0
--- /dev/null
+++ b/has-arrow-function-support/examples/index.js
@@ -0,0 +1,28 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+var hasArrowFunctionSupport = require( './../lib' );
+
+var bool = hasArrowFunctionSupport();
+if ( bool ) {
+ console.log( 'Environment has native arrow function support.' );
+} else {
+ console.log( 'Environment lacks native arrow function support.' );
+}
diff --git a/has-arrow-function-support/lib/index.js b/has-arrow-function-support/lib/index.js
new file mode 100644
index 00000000..6b3a0222
--- /dev/null
+++ b/has-arrow-function-support/lib/index.js
@@ -0,0 +1,40 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+/**
+* Test for native arrow function support.
+*
+* @module @stdlib/assert/has-arrow-function-support
+*
+* @example
+* var hasArrowFunctionSupport = require( '@stdlib/assert/has-arrow-function-support' );
+*
+* var bool = hasArrowFunctionSupport();
+* // returns
+*/
+
+// MODULES //
+
+var hasArrowFunctionSupport = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = hasArrowFunctionSupport;
diff --git a/has-arrow-function-support/lib/main.js b/has-arrow-function-support/lib/main.js
new file mode 100644
index 00000000..9113a47c
--- /dev/null
+++ b/has-arrow-function-support/lib/main.js
@@ -0,0 +1,51 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var evil = require( '@stdlib/utils/eval' );
+
+
+// MAIN //
+
+/**
+* Tests for native arrow function support.
+*
+* @returns {boolean} boolean indicating if an environment has native arrow function support
+*
+* @example
+* var bool = hasArrowFunctionSupport();
+* // returns
+*/
+function hasArrowFunctionSupport() {
+ var bool;
+ try {
+ evil( '"use strict"; (() => {})' );
+ bool = true;
+ } catch ( err ) { // eslint-disable-line no-unused-vars
+ bool = false;
+ }
+ return bool;
+}
+
+
+// EXPORTS //
+
+module.exports = hasArrowFunctionSupport;
diff --git a/has-arrow-function-support/package.json b/has-arrow-function-support/package.json
new file mode 100644
index 00000000..5fac5446
--- /dev/null
+++ b/has-arrow-function-support/package.json
@@ -0,0 +1,78 @@
+{
+ "name": "@stdlib/assert/has-arrow-function-support",
+ "version": "0.0.0",
+ "description": "Detect native arrow function support.",
+ "license": "Apache-2.0",
+ "author": {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ },
+ "contributors": [
+ {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ }
+ ],
+ "bin": {
+ "has-arrow-function-support": "./bin/cli"
+ },
+ "main": "./lib",
+ "directories": {
+ "benchmark": "./benchmark",
+ "bin": "./bin",
+ "doc": "./docs",
+ "example": "./examples",
+ "lib": "./lib",
+ "test": "./test"
+ },
+ "types": "./docs/types",
+ "scripts": {},
+ "homepage": "https://github.com/stdlib-js/stdlib",
+ "repository": {
+ "type": "git",
+ "url": "git://github.com/stdlib-js/stdlib.git"
+ },
+ "bugs": {
+ "url": "https://github.com/stdlib-js/stdlib/issues"
+ },
+ "dependencies": {},
+ "devDependencies": {},
+ "engines": {
+ "node": ">=0.10.0",
+ "npm": ">2.7.0"
+ },
+ "os": [
+ "aix",
+ "darwin",
+ "freebsd",
+ "linux",
+ "macos",
+ "openbsd",
+ "sunos",
+ "win32",
+ "windows"
+ ],
+ "keywords": [
+ "stdlib",
+ "stdutils",
+ "stdutil",
+ "utilities",
+ "utility",
+ "utils",
+ "util",
+ "detect",
+ "feature",
+ "arrow",
+ "arrow function",
+ "yield",
+ "es2015",
+ "es6",
+ "support",
+ "has",
+ "hasarrowfunction",
+ "hasarrowfunctions",
+ "native",
+ "issupported",
+ "cli"
+ ]
+}
diff --git a/has-arrow-function-support/test/test.cli.js b/has-arrow-function-support/test/test.cli.js
new file mode 100644
index 00000000..2377fff1
--- /dev/null
+++ b/has-arrow-function-support/test/test.cli.js
@@ -0,0 +1,163 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var resolve = require( 'path' ).resolve;
+var exec = require( 'child_process' ).exec;
+var tape = require( 'tape' );
+var IS_BROWSER = require( './../../is-browser' );
+var IS_WINDOWS = require( './../../is-windows' );
+var EXEC_PATH = require( '@stdlib/process/exec-path' );
+var readFileSync = require( '@stdlib/fs/read-file' ).sync;
+
+
+// VARIABLES //
+
+var fpath = resolve( __dirname, '..', 'bin', 'cli' );
+var opts = {
+ 'skip': IS_BROWSER || IS_WINDOWS
+};
+
+
+// FIXTURES //
+
+var PKG_VERSION = require( './../package.json' ).version;
+
+
+// TESTS //
+
+tape( 'command-line interface', function test( t ) {
+ t.ok( true, __filename );
+ t.end();
+});
+
+tape( 'when invoked with a `--help` flag, the command-line interface prints the help text to `stderr`', opts, function test( t ) {
+ var expected;
+ var cmd;
+
+ expected = readFileSync( resolve( __dirname, '..', 'docs', 'usage.txt' ), {
+ 'encoding': 'utf8'
+ });
+ cmd = [
+ EXEC_PATH,
+ fpath,
+ '--help'
+ ];
+
+ exec( cmd.join( ' ' ), done );
+
+ function done( error, stdout, stderr ) {
+ if ( error ) {
+ t.fail( error.message );
+ } else {
+ t.strictEqual( stdout.toString(), '', 'does not print to `stdout`' );
+ t.strictEqual( stderr.toString(), expected+'\n', 'expected value' );
+ }
+ t.end();
+ }
+});
+
+tape( 'when invoked with a `-h` flag, the command-line interface prints the help text to `stderr`', opts, function test( t ) {
+ var expected;
+ var cmd;
+
+ expected = readFileSync( resolve( __dirname, '..', 'docs', 'usage.txt' ), {
+ 'encoding': 'utf8'
+ });
+ cmd = [
+ EXEC_PATH,
+ fpath,
+ '-h'
+ ];
+
+ exec( cmd.join( ' ' ), done );
+
+ function done( error, stdout, stderr ) {
+ if ( error ) {
+ t.fail( error.message );
+ } else {
+ t.strictEqual( stdout.toString(), '', 'does not print to `stdout`' );
+ t.strictEqual( stderr.toString(), expected+'\n', 'expected value' );
+ }
+ t.end();
+ }
+});
+
+tape( 'when invoked with a `--version` flag, the command-line interface prints the version to `stderr`', opts, function test( t ) {
+ var cmd = [
+ EXEC_PATH,
+ fpath,
+ '--version'
+ ];
+
+ exec( cmd.join( ' ' ), done );
+
+ function done( error, stdout, stderr ) {
+ if ( error ) {
+ t.fail( error.message );
+ } else {
+ t.strictEqual( stdout.toString(), '', 'does not print to `stdout`' );
+ t.strictEqual( stderr.toString(), PKG_VERSION+'\n', 'expected value' );
+ }
+ t.end();
+ }
+});
+
+tape( 'when invoked with a `-V` flag, the command-line interface prints the version to `stderr`', opts, function test( t ) {
+ var cmd = [
+ EXEC_PATH,
+ fpath,
+ '-V'
+ ];
+
+ exec( cmd.join( ' ' ), done );
+
+ function done( error, stdout, stderr ) {
+ if ( error ) {
+ t.fail( error.message );
+ } else {
+ t.strictEqual( stdout.toString(), '', 'does not print to `stdout`' );
+ t.strictEqual( stderr.toString(), PKG_VERSION+'\n', 'expected value' );
+ }
+ t.end();
+ }
+});
+
+tape( 'the command-line interface prints either `true` or `false` to `stdout` indicating whether an environment provides native `() => {}` support', opts, function test( t ) {
+ var cmd = [
+ EXEC_PATH,
+ fpath
+ ];
+
+ exec( cmd.join( ' ' ), done );
+
+ function done( error, stdout, stderr ) {
+ var str;
+ if ( error ) {
+ t.fail( error.message );
+ } else {
+ str = stdout.toString();
+ t.strictEqual( str === 'true\n' || str === 'false\n', true, 'prints either `true` or `false` to `stdout`' );
+ t.strictEqual( stderr.toString(), '', 'does not print to `stderr`' );
+ }
+ t.end();
+ }
+});
diff --git a/has-arrow-function-support/test/test.js b/has-arrow-function-support/test/test.js
new file mode 100644
index 00000000..83fa2bbf
--- /dev/null
+++ b/has-arrow-function-support/test/test.js
@@ -0,0 +1,65 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var tape = require( 'tape' );
+var proxyquire = require( 'proxyquire' );
+var detect = require( './../lib' );
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+ t.ok( true, __filename );
+ t.strictEqual( typeof detect, 'function', 'main export is a function' );
+ t.end();
+});
+
+tape( 'feature detection result is a boolean', function test( t ) {
+ t.strictEqual( typeof detect(), 'boolean', 'detection result is a boolean' );
+ t.end();
+});
+
+tape( 'if `() => {}` is supported, detection result is `true`', function test( t ) {
+ var detect = proxyquire( './../lib/main.js', {
+ '@stdlib/utils/eval': stub
+ });
+
+ t.ok( detect(), 'detection result is `true`' );
+ t.end();
+
+ function stub() {
+ return 'beep';
+ }
+});
+
+tape( 'if `() => {}` is not supported, detection result is `false`', function test( t ) {
+ var detect = proxyquire( './../lib/main.js', {
+ '@stdlib/utils/eval': stub
+ });
+
+ t.notOk( detect(), 'detection result is `false`' );
+ t.end();
+
+ function stub() {
+ throw new Error( 'boop' );
+ }
+});
diff --git a/is-arrow-function/README.md b/is-arrow-function/README.md
new file mode 100644
index 00000000..ed10995f
--- /dev/null
+++ b/is-arrow-function/README.md
@@ -0,0 +1,105 @@
+
+
+# isArrowFunction
+
+> Test if a value is an [`arrow function`][mdn-arrow-function].
+
+
+
+## Usage
+
+```javascript
+var isArrowFunction = require( '@stdlib/assert/is-arrow-function' );
+```
+
+#### isArrowFunction( value )
+
+Tests if a `value` is a an [`arrow function`][mdn-arrow-function] such as `( a, b ) => a + b`, `x => x`, or `( x ) => { return x*x; }`.
+
+
+
+```javascript
+var beep = () => {
+ console.log( 'beep' );
+};
+
+var bool = isArrowFunction( beep );
+// returns true
+
+function boop() {
+ console.log( 'boop' );
+}
+
+bool = isArrowFunction( boop );
+// returns false
+```
+
+
+
+
+
+
+
+## Examples
+
+
+
+
+
+```javascript
+var isArrowFunction = require( '@stdlib/assert/is-arrow-function' );
+
+var bool = isArrowFunction( () => {} );
+// returns true
+
+bool = isArrowFunction( function foo() {} );
+// returns false
+
+bool = isArrowFunction( 'beep' );
+// returns false
+
+bool = isArrowFunction( 5 );
+// returns false
+
+bool = isArrowFunction( true );
+// returns false
+
+bool = isArrowFunction( null );
+// returns false
+
+bool = isArrowFunction( [] );
+// returns false
+
+bool = isArrowFunction( {} );
+// returns false
+```
+
+
+
+
+
+
+
+[mdn-arrow-function]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions
+
+
+
+
diff --git a/is-arrow-function/benchmark/benchmark.js b/is-arrow-function/benchmark/benchmark.js
new file mode 100644
index 00000000..4aa6887e
--- /dev/null
+++ b/is-arrow-function/benchmark/benchmark.js
@@ -0,0 +1,78 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-empty-function */
+
+'use strict';
+
+// MODULES //
+
+var bench = require( '@stdlib/bench' );
+var evil = require( '@stdlib/utils/eval' );
+var hasArrowFunctionSupport = require( './../../has-arrow-function-support' );
+var isBoolean = require( './../../is-boolean' ).isPrimitive;
+var pkg = require( './../package.json' ).name;
+var isArrowFunction = require( './../lib' );
+
+
+// FUNCTIONS //
+
+function createArrowFunction() {
+ return evil( '( () => {} )' );
+}
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+ var values;
+ var bool;
+ var i;
+
+ values = [
+ '5',
+ 5,
+ NaN,
+ true,
+ false,
+ null,
+ void 0,
+ [],
+ {},
+ new Date(),
+ function noop() {}
+ ];
+ if ( hasArrowFunctionSupport() ) {
+ values.push( createArrowFunction() );
+ }
+
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ bool = isArrowFunction( values[ i%values.length ] );
+ if ( !isBoolean( bool ) ) {
+ b.fail( 'should return a boolean' );
+ }
+ }
+ b.toc();
+ if ( isBoolean( bool ) ) {
+ b.pass( 'benchmark finished' );
+ } else {
+ b.fail( 'should return a boolean' );
+ }
+ b.end();
+});
diff --git a/is-arrow-function/docs/repl.txt b/is-arrow-function/docs/repl.txt
new file mode 100644
index 00000000..df1d8c0d
--- /dev/null
+++ b/is-arrow-function/docs/repl.txt
@@ -0,0 +1,25 @@
+
+{{alias}}( value )
+ Tests if a value is an arrow function.
+
+ Parameters
+ ----------
+ value: any
+ Value to test.
+
+ Returns
+ -------
+ bool: boolean
+ Boolean indicating whether value is an arrow function.
+
+ Examples
+ --------
+ > function beep() {};
+ > var bool = {{alias}}( beep )
+ false
+ > bool = {{alias}}( {} )
+ false
+
+ See Also
+ --------
+
diff --git a/is-arrow-function/docs/types/index.d.ts b/is-arrow-function/docs/types/index.d.ts
new file mode 100644
index 00000000..f5787421
--- /dev/null
+++ b/is-arrow-function/docs/types/index.d.ts
@@ -0,0 +1,45 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+// TypeScript Version: 2.0
+
+/**
+* Tests if a value is an arrow function.
+*
+* @param value - value to test
+* @returns boolean indicating whether value is an arrow function
+*
+* @example
+* var arrow = () => {};
+* var bool = isArrowFunction( arrow );
+* // returns true
+*
+* @example
+* function beep() {
+* return 'beep';
+* }
+
+* var bool = isArrowFunction( beep );
+* // returns false
+*/
+declare function isArrowFunction( value: any ): boolean;
+
+
+// EXPORTS //
+
+export = isArrowFunction;
diff --git a/is-arrow-function/docs/types/test.ts b/is-arrow-function/docs/types/test.ts
new file mode 100644
index 00000000..468f813a
--- /dev/null
+++ b/is-arrow-function/docs/types/test.ts
@@ -0,0 +1,34 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+import isArrowFunction = require( './index' );
+
+
+// TESTS //
+
+// The function returns a boolean...
+{
+ isArrowFunction( ( x: number ) => x ); // $ExpectType boolean
+ isArrowFunction( [] ); // $ExpectType boolean
+}
+
+// The compiler throws an error if the function is provided an unsupported number of arguments...
+{
+ isArrowFunction(); // $ExpectError
+ isArrowFunction( ( x: number ) => x, 123 ); // $ExpectError
+}
diff --git a/is-arrow-function/examples/index.js b/is-arrow-function/examples/index.js
new file mode 100644
index 00000000..ef6959c6
--- /dev/null
+++ b/is-arrow-function/examples/index.js
@@ -0,0 +1,55 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-empty-function, no-restricted-syntax */
+
+'use strict';
+
+var hasArrowFunctionSupport = require( './../../has-arrow-function-support' );
+var evil = require( '@stdlib/utils/eval' );
+var isArrowFunction = require( './../lib' );
+
+function createArrowFunction() {
+ return evil( '( () => {} )' );
+}
+
+if ( hasArrowFunctionSupport() ) {
+ console.log( isArrowFunction( createArrowFunction() ) );
+ // => true
+}
+
+console.log( isArrowFunction( function foo() {} ) );
+// => false
+
+console.log( isArrowFunction( 'beep' ) );
+// => false
+
+console.log( isArrowFunction( 5 ) );
+// => false
+
+console.log( isArrowFunction( true ) );
+// => false
+
+console.log( isArrowFunction( null ) );
+// => false
+
+console.log( isArrowFunction( [] ) );
+// => false
+
+console.log( isArrowFunction( {} ) );
+// => false
diff --git a/is-arrow-function/lib/index.js b/is-arrow-function/lib/index.js
new file mode 100644
index 00000000..7543a4f0
--- /dev/null
+++ b/is-arrow-function/lib/index.js
@@ -0,0 +1,49 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+/**
+* Test if a value is an arrow function.
+*
+* @module @stdlib/assert/is-arrow-function
+*
+* @example
+* var isArrowFunction = require( '@stdlib/assert/is-arrow-function' );
+*
+* var beep = () => 'beep';
+*
+* var bool = isArrowFunction( beep );
+* // returns true
+
+* function boop() {
+* return 'boop';
+* }
+*
+* bool = isArrowFunction( boop );
+* // returns false
+*/
+
+// MODULES //
+
+var isArrowFunction = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = isArrowFunction;
diff --git a/is-arrow-function/lib/main.js b/is-arrow-function/lib/main.js
new file mode 100644
index 00000000..1d2cec09
--- /dev/null
+++ b/is-arrow-function/lib/main.js
@@ -0,0 +1,67 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var isFunction = require( './../../is-function' );
+
+
+// VARIABLES //
+
+var RE_ARROW_FUNCTION = /^(?:\([^)]*\) *|[^=]*)=>/;
+
+// Using `Function#toString` bypasses a value's own `toString` method to provide an extra, but not security proof, precaution to prevent a provided function from impersonating an arrow function:
+var fcn2str = Function.prototype.toString;
+
+
+// MAIN //
+
+/**
+* Tests whether a value is an arrow function.
+*
+* @param {*} value - value to test
+* @returns {boolean} boolean indicating whether a value is an arrow function
+*
+* @example
+* var arrow = () => {};
+* var bool = isArrowFunction( arrow );
+* // returns true
+*
+* @example
+* function beep() {
+* return 'beep';
+* }
+
+* var bool = isArrowFunction( beep );
+* // returns false
+*/
+function isArrowFunction( value ) {
+ var str;
+ if ( !isFunction( value ) ) {
+ return false;
+ }
+ str = fcn2str.call( value );
+ return RE_ARROW_FUNCTION.test( str );
+}
+
+
+// EXPORTS //
+
+module.exports = isArrowFunction;
diff --git a/is-arrow-function/package.json b/is-arrow-function/package.json
new file mode 100644
index 00000000..0dd0b7ed
--- /dev/null
+++ b/is-arrow-function/package.json
@@ -0,0 +1,71 @@
+{
+ "name": "@stdlib/assert/is-arrow-function",
+ "version": "0.0.0",
+ "description": "Test if a value is an arrow function.",
+ "license": "Apache-2.0",
+ "author": {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ },
+ "contributors": [
+ {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ }
+ ],
+ "main": "./lib",
+ "directories": {
+ "benchmark": "./benchmark",
+ "doc": "./docs",
+ "example": "./examples",
+ "lib": "./lib",
+ "test": "./test"
+ },
+ "types": "./docs/types",
+ "scripts": {},
+ "homepage": "https://github.com/stdlib-js/stdlib",
+ "repository": {
+ "type": "git",
+ "url": "git://github.com/stdlib-js/stdlib.git"
+ },
+ "bugs": {
+ "url": "https://github.com/stdlib-js/stdlib/issues"
+ },
+ "dependencies": {},
+ "devDependencies": {},
+ "engines": {
+ "node": ">=0.10.0",
+ "npm": ">2.7.0"
+ },
+ "os": [
+ "aix",
+ "darwin",
+ "freebsd",
+ "linux",
+ "macos",
+ "openbsd",
+ "sunos",
+ "win32",
+ "windows"
+ ],
+ "keywords": [
+ "stdlib",
+ "stdassert",
+ "assertion",
+ "assert",
+ "utilities",
+ "utility",
+ "utils",
+ "util",
+ "function",
+ "is",
+ "isfunction",
+ "arrow",
+ "arrowfunction",
+ "type",
+ "check",
+ "valid",
+ "validate",
+ "test"
+ ]
+}
diff --git a/is-arrow-function/test/es2015-arrow-function/index.js b/is-arrow-function/test/es2015-arrow-function/index.js
new file mode 100644
index 00000000..77623b1d
--- /dev/null
+++ b/is-arrow-function/test/es2015-arrow-function/index.js
@@ -0,0 +1,34 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+/* eslint-disable */
+
+// MODULES //
+
+var tape = require( 'tape' );
+var isArrowFunction = require( './../../lib' );
+
+
+// TESTS //
+
+tape( 'the function returns `true` if provided an arrow function', function test( t ) {
+ t.equal( isArrowFunction( () => {} ), true, 'returns true' );
+ t.end();
+});
diff --git a/is-arrow-function/test/test.js b/is-arrow-function/test/test.js
new file mode 100644
index 00000000..eda8d407
--- /dev/null
+++ b/is-arrow-function/test/test.js
@@ -0,0 +1,96 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var tape = require( 'tape' );
+var arrowFunctionSupport = require( './../../has-arrow-function-support' );
+var isArrowFunction = require( './../lib' );
+
+
+// VARIABLES //
+
+var hasArrowFunctions = arrowFunctionSupport();
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+ t.ok( true, __filename );
+ t.strictEqual( typeof isArrowFunction, 'function', 'main export is a function' );
+ t.end();
+});
+
+// Run arrow function tests if environment supports `() => {}`...
+
+if ( hasArrowFunctions ) {
+ require( './es2015-arrow-function' ); // eslint-disable-line stdlib/no-unassigned-require
+}
+
+tape( 'the function returns `false` if provided a function trying to impersonate an arrow function', function test( t ) {
+ function pretend() {}
+ pretend.toString = function toString() {
+ return '() => {}';
+ };
+ t.strictEqual( isArrowFunction( pretend ), false, 'returns false' );
+ t.end();
+});
+
+tape( 'the function returns `false` if provided a function which is not an arrow function', function test( t ) {
+ // eslint-disable-next-line func-style, func-names
+ var beep = function () {
+ return 'boop';
+ };
+ t.strictEqual( isArrowFunction( beep ), false, 'returns false' );
+
+ beep = function beep() {
+ return 'boop';
+ };
+ t.strictEqual( isArrowFunction( beep ), false, 'returns false' );
+
+ function baz() {
+ return 'boop';
+ }
+ t.strictEqual( isArrowFunction( baz ), false, 'returns false' );
+
+ t.end();
+});
+
+tape( 'the function returns `false` if not provided a function', function test( t ) {
+ var values;
+ var i;
+
+ values = [
+ '5',
+ 5,
+ NaN,
+ void 0,
+ true,
+ false,
+ null,
+ [],
+ {}
+ ];
+
+ for ( i = 0; i < values.length; i++ ) {
+ t.strictEqual( isArrowFunction( values[i] ), false, 'returns false when provided '+values[i] );
+ }
+ t.end();
+});
diff --git a/is-class/benchmark/benchmark.js b/is-class/benchmark/benchmark.js
index a21d47ff..78db5d8d 100644
--- a/is-class/benchmark/benchmark.js
+++ b/is-class/benchmark/benchmark.js
@@ -22,10 +22,19 @@
var bench = require( '@stdlib/bench' );
var isBoolean = require( './../../is-boolean' ).isPrimitive;
+var evil = require( '@stdlib/utils/eval' );
+var hasClassSupport = require( './../../has-class-support' );
var pkg = require( './../package.json' ).name;
var isClass = require( './../lib' );
+// FUNCTIONS //
+
+function createClass() {
+ return evil( '(class Person {})' );
+}
+
+
// MAIN //
bench( pkg, function benchmark( b ) {
@@ -34,7 +43,6 @@ bench( pkg, function benchmark( b ) {
var i;
values = [
- class Person {}, // eslint-disable-line no-restricted-syntax
function Person() {}, // eslint-disable-line no-empty-function
'5',
5,
@@ -44,6 +52,9 @@ bench( pkg, function benchmark( b ) {
null,
void 0
];
+ if ( hasClassSupport() ) {
+ values.push( createClass() );
+ }
b.tic();
for ( i = 0; i < b.iterations; i++ ) {
diff --git a/is-class/examples/index.js b/is-class/examples/index.js
index d6360cfc..cb1a8d78 100644
--- a/is-class/examples/index.js
+++ b/is-class/examples/index.js
@@ -20,11 +20,21 @@
'use strict';
+var hasClassSupport = require( './../../has-class-support' );
+var evil = require( '@stdlib/utils/eval' );
var isClass = require( './../lib' );
-var bool = isClass( class Person {} );
-console.log( bool );
-// => true
+function createClass() {
+ return evil( '(class Person {})' );
+}
+
+var bool;
+
+if ( hasClassSupport() ) {
+ bool = isClass( createClass() );
+ console.log( bool );
+ // => true
+}
bool = isClass( function Person() {} );
console.log( bool );
diff --git a/is-class/test/es2015-class/index.js b/is-class/test/es2015-class/index.js
new file mode 100644
index 00000000..65c64d85
--- /dev/null
+++ b/is-class/test/es2015-class/index.js
@@ -0,0 +1,37 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2021 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-restricted-syntax, max-classes-per-file */
+
+'use strict';
+
+// MODULES //
+
+var tape = require( 'tape' );
+var isClass = require( './../../lib' );
+
+
+// TESTS //
+
+tape( 'the function returns `true` if provided an ES2015 class', function test( t ) {
+ var Rectangle = class {};
+ t.strictEqual( isClass( Rectangle ), true, 'returns true' );
+
+ t.strictEqual( isClass( class Person {} ), true, 'returns true' );
+ t.end();
+});
diff --git a/is-class/test/test.js b/is-class/test/test.js
index 6f95364c..f5434856 100644
--- a/is-class/test/test.js
+++ b/is-class/test/test.js
@@ -21,9 +21,15 @@
// MODULES //
var tape = require( 'tape' );
+var detectClassSupport = require( './../../has-class-support' );
var isClass = require( './../lib' );
+// VARIABLES //
+
+var hasClassSupport = detectClassSupport();
+
+
// TESTS //
tape( 'main export is a function', function test( t ) {
@@ -32,12 +38,7 @@ tape( 'main export is a function', function test( t ) {
t.end();
});
-tape( 'the function returns `true` if provided is a class', function test( t ) {
- t.strictEqual( isClass( class Person {} ), true, 'returns true' ); // eslint-disable-line no-restricted-syntax
- t.end();
-});
-
-tape( 'the function returns `false` if not provided an ES6 class', function test( t ) {
+tape( 'the function returns `false` if not provided an ES2015 class', function test( t ) {
var values;
var i;
@@ -59,3 +60,9 @@ tape( 'the function returns `false` if not provided an ES6 class', function test
}
t.end();
});
+
+// Run positive tests if environment supports class...
+
+if ( hasClassSupport ) {
+ require( './es2015-class' ); // eslint-disable-line stdlib/no-unassigned-require
+}
diff --git a/lib/index.js b/lib/index.js
index 6f1617f6..1a54cd94 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -81,6 +81,15 @@ setReadOnly( ns, 'deepHasProp', require( './../deep-has-property' ) );
*/
setReadOnly( ns, 'hasArrayBufferSupport', require( './../has-arraybuffer-support' ) );
+/**
+* @name hasArrowFunctionSupport
+* @memberof ns
+* @readonly
+* @type {Function}
+* @see {@link module:@stdlib/assert/has-arrow-function-support}
+*/
+setReadOnly( ns, 'hasArrowFunctionSupport', require( './../has-arrow-function-support' ) );
+
/**
* @name hasAsyncAwaitSupport
* @memberof ns
@@ -531,6 +540,15 @@ setReadOnly( ns, 'isArrayBuffer', require( './../is-arraybuffer' ) );
*/
setReadOnly( ns, 'isArrayBufferView', require( './../is-arraybuffer-view' ) );
+/**
+* @name isArrowFunction
+* @memberof ns
+* @readonly
+* @type {Function}
+* @see {@link module:@stdlib/assert/is-arrow-function}
+*/
+setReadOnly( ns, 'isArrowFunction', require( './../is-arrow-function' ) );
+
/**
* @name isASCII
* @memberof ns