diff --git a/base/replace-before-last/README.md b/base/replace-before-last/README.md
new file mode 100644
index 00000000..888586ee
--- /dev/null
+++ b/base/replace-before-last/README.md
@@ -0,0 +1,136 @@
+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2024 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.
+
+-->
+
+# replaceBeforeLast
+
+> Replace the substring before the last occurrence of a specified search string.
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- Package usage documentation. -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var replaceBeforeLast = require( '@stdlib/string/base/replace-before-last' );
+```
+
+#### replaceBeforeLast( str, search, replacement, fromIndex )
+
+Replaces the substring before the last occurrence of a specified search string.
+
+```javascript
+var str = 'beep boop';
+var out = replaceBeforeLast( str, ' ', 'loop', str.length );
+// returns 'loop boop'
+
+out = replaceBeforeLast( str, 'o', 'bar', str.length );
+// returns 'barop'
+```
+
+The search starts at the end of the string and proceeds backwards to the beginning. To start the search at a specified index, specify an integer for the `fromIndex` argument.
+
+```javascript
+var str = 'beep boop beep';
+var out = replaceBeforeLast( str, ' ', 'loop', 5 );
+// returns 'loop boop beep'
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+## Notes
+
+-   If a search string is not present in a provided string, the function returns the provided string unchanged.
+-   If a search string is an empty string, the function returns the provided string unchanged.
+-   If `fromIndex` is less than `0`, the function returns the provided string unchanged.
+
+</section>
+
+<!-- /.notes -->
+
+<!-- Package usage examples. -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var replaceBeforeLast = require( '@stdlib/string/base/replace-before-last' );
+
+var str = 'beep boop';
+var out = replaceBeforeLast( str, 'p', 'see', str.length );
+// returns 'seep'
+
+str = 'Hello World!';
+out = replaceBeforeLast( str, 'xyz', 'foo', str.length );
+// returns 'Hello World!'
+
+str = 'Hello World!';
+out = replaceBeforeLast( str, '', 'foo', str.length );
+// returns 'Hello World!'
+
+str = '';
+out = replaceBeforeLast( str, 'xyz', 'foo', str.length );
+// returns ''
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="references">
+
+</section>
+
+<!-- /.references -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="links">
+
+</section>
+
+<!-- /.links -->
diff --git a/base/replace-before-last/benchmark/benchmark.js b/base/replace-before-last/benchmark/benchmark.js
new file mode 100644
index 00000000..052ee531
--- /dev/null
+++ b/base/replace-before-last/benchmark/benchmark.js
@@ -0,0 +1,58 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 isString = require( '@stdlib/assert/is-string' ).isPrimitive;
+var pkg = require( './../package.json' ).name;
+var replaceBeforeLast = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var values;
+	var out;
+	var str;
+	var i;
+
+	str = 'To be, or not to be, that is the question.';
+	values = [
+		'foo',
+		'bar',
+		'beep',
+		'boop'
+	];
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = replaceBeforeLast( str, 'T', values[ i%values.length ], str.length );
+		if ( typeof out !== 'string' ) {
+			b.fail( 'should return a string' );
+		}
+	}
+	b.toc();
+	if ( !isString( out ) ) {
+		b.fail( 'should return a string' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
diff --git a/base/replace-before-last/docs/repl.txt b/base/replace-before-last/docs/repl.txt
new file mode 100644
index 00000000..a2dda150
--- /dev/null
+++ b/base/replace-before-last/docs/repl.txt
@@ -0,0 +1,37 @@
+
+{{alias}}( str, search, replacement, fromIndex )
+    Replaces the substring before the last occurrence of a specified search
+    string.
+
+    Parameters
+    ----------
+    str: string
+        Input string.
+
+    search: string
+        Search string.
+
+    replacement: string
+        Replacement string.
+
+    fromIndex: integer
+        Index from which to start searching.
+
+    Returns
+    -------
+    out: string
+        Output string.
+
+    Examples
+    --------
+    > var str = 'beep boop';
+    > var out = {{alias}}( str, ' ', 'foo', str.length )
+    'foo boop'
+    > out = {{alias}}( str, 'o', 'foo', str.length )
+    'fooop'
+    > out = {{alias}}( 'Hello World!', 'o', 'foo', 5 )
+    'fooo World!'
+
+    See Also
+    --------
+
diff --git a/base/replace-before-last/docs/types/index.d.ts b/base/replace-before-last/docs/types/index.d.ts
new file mode 100644
index 00000000..a89dbdaa
--- /dev/null
+++ b/base/replace-before-last/docs/types/index.d.ts
@@ -0,0 +1,65 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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: 4.1
+
+/**
+* Replaces the substring before the last occurrence of a specified search string.
+*
+* @param str - input string
+* @param search - search string
+* @param replacement - replacement string
+* @param fromIndex - index from which to start searching
+* @returns output string
+*
+* @example
+* var str = 'beep boop';
+* var out = replaceBeforeLast( str, ' ', 'foo', str.length );
+* // returns 'foo boop'
+*
+* @example
+* var str = 'beep boop';
+* var out = replaceBeforeLast( str, 'p', 'foo', str.length );
+* // returns 'foop'
+*
+* @example
+* var str = 'Hello World!';
+* var out = replaceBeforeLast( str, '', 'foo',  str.length );
+* // returns 'Hello World!'
+*
+* @example
+* var str = 'Hello World!';
+* var out = replaceBeforeLast( str, 'xyz', 'foo', str.length );
+* // returns 'Hello World!'
+*
+* @example
+* var str = 'beep boop baz';
+* var out = replaceBeforeLast( str, 'p b', 'foo', str.length );
+* // returns 'foop baz'
+*
+* @example
+* var str = 'beep boop baz';
+* var out = replaceBeforeLast( str, 'p b', 'foo', 6 );
+* // returns 'foop boop baz'
+*/
+declare function replaceBeforeLast( str: string, search: string, replacement: string, fromIndex: number ): string;
+
+
+// EXPORTS //
+
+export = replaceBeforeLast;
diff --git a/base/replace-before-last/docs/types/test.ts b/base/replace-before-last/docs/types/test.ts
new file mode 100644
index 00000000..4e76a173
--- /dev/null
+++ b/base/replace-before-last/docs/types/test.ts
@@ -0,0 +1,69 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 replaceBeforeLast = require( './index' );
+
+
+// TESTS //
+
+// The function returns a string...
+{
+	replaceBeforeLast( 'beep boop', ' ', 'foo', 10 ); // $ExpectType string
+	replaceBeforeLast( 'beep boop', 'xyz', 'foo', 10 ); // $ExpectType string
+	replaceBeforeLast( 'beep boop', '', 'foo', 10 ); // $ExpectType string
+}
+
+// The compiler throws an error if the function is provided arguments having invalid types...
+{
+	replaceBeforeLast( true, 'd', 'foo', 100 ); // $ExpectError
+	replaceBeforeLast( false, 'd' , 'foo', 100 ); // $ExpectError
+	replaceBeforeLast( 3, 'd' , 'foo', 100 ); // $ExpectError
+	replaceBeforeLast( [], 'd' , 'foo', 100 ); // $ExpectError
+	replaceBeforeLast( {}, 'd' , 'foo', 100 ); // $ExpectError
+	replaceBeforeLast( ( x: number ): number => x, 'd', 'foo', 100 ); // $ExpectError
+
+	replaceBeforeLast( 'abc', true, 'foo', 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', false, 'foo', 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', 5 , 'foo', 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', [], 'foo', 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', {} , 'foo', 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', ( x: number ): number => x , 'foo', 10 ); // $ExpectError
+
+	replaceBeforeLast( 'abc', 'd', true, 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', false, 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', 5, 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', [], 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', {}, 10 ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', ( x: number ): number => x, 10 ); // $ExpectError
+
+	replaceBeforeLast( 'abc', 'd', 'foo', true ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', 'foo', false ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', 'foo', '5' ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', 'foo', [] ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', 'foo', {} ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', 'foo', ( x: number ): number => x ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided insufficient arguments...
+{
+	replaceBeforeLast(); // $ExpectError
+	replaceBeforeLast( 'abc' ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd' ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', 'foo' ); // $ExpectError
+	replaceBeforeLast( 'abc', 'd', 'foo', 4, 4 ); // $ExpectError
+}
diff --git a/base/replace-before-last/examples/index.js b/base/replace-before-last/examples/index.js
new file mode 100644
index 00000000..7e11cb4c
--- /dev/null
+++ b/base/replace-before-last/examples/index.js
@@ -0,0 +1,51 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 replaceBeforeLast = require( './../lib' );
+
+var str = 'beep boop';
+var out = replaceBeforeLast( str, 'p', 'see', str.length );
+console.log( out );
+// => 'seep'
+
+str = 'Hello World!';
+out = replaceBeforeLast( str, 'xyz', 'foo', str.length );
+console.log( out );
+// => 'Hello World!'
+
+str = 'Hello World!';
+out = replaceBeforeLast( str, '', 'foo', str.length );
+console.log( out );
+// => 'Hello World!'
+
+str = '';
+out = replaceBeforeLast( str, 'xyz', 'foo', str.length );
+console.log( out );
+// => ''
+
+str = 'beep boop baz';
+out = replaceBeforeLast( str, 'p b', 'foo', str.length );
+console.log( out );
+// => 'foop baz'
+
+str = 'beep boop baz';
+out = replaceBeforeLast( str, 'p b', 'foo', 6 );
+console.log( out );
+// => 'foop boop baz'
diff --git a/base/replace-before-last/lib/index.js b/base/replace-before-last/lib/index.js
new file mode 100644
index 00000000..b29877c0
--- /dev/null
+++ b/base/replace-before-last/lib/index.js
@@ -0,0 +1,45 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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';
+
+/**
+* Replace the substring before the last occurrence of a specified search string.
+*
+* @module @stdlib/string/base/replace-before-last
+*
+* @example
+* var replaceBeforeLast = require( '@stdlib/string/base/replace-before-last' );
+*
+* var str = 'beep boop';
+*
+* var out = replaceBeforeLast( str, ' ', 'foo', str.length );
+* // returns 'foo boop'
+*
+* out = replaceBeforeLast( str, 'o', 'bar', str.length );
+* // returns 'barop'
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/base/replace-before-last/lib/main.js b/base/replace-before-last/lib/main.js
new file mode 100644
index 00000000..fd03f8fa
--- /dev/null
+++ b/base/replace-before-last/lib/main.js
@@ -0,0 +1,77 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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';
+
+// MAIN //
+
+/**
+* Replaces the substring before the last occurrence of a specified search string.
+*
+* @param {string} str - input string
+* @param {string} search - search string
+* @param {string} replacement - replacement string
+* @param {integer} fromIndex - index from which to start searching
+* @returns {string} string
+*
+* @example
+* var str = 'beep boop';
+* var out = replaceBeforeLast( str, ' ', 'foo', str.length );
+* // returns 'foo boop'
+*
+* @example
+* var str = 'beep boop';
+* var out = replaceBeforeLast( str, 'p', 'foo', str.length );
+* // returns 'foop'
+*
+* @example
+* var str = 'Hello World!';
+* var out = replaceBeforeLast( str, '', 'foo',  str.length );
+* // returns 'Hello World!'
+*
+* @example
+* var str = 'Hello World!';
+* var out = replaceBeforeLast( str, 'xyz', 'foo', str.length );
+* // returns 'Hello World!'
+*
+* @example
+* var str = 'beep boop baz';
+* var out = replaceBeforeLast( str, 'p b', 'foo', str.length );
+* // returns 'foop baz'
+*
+* @example
+* var str = 'beep boop baz';
+* var out = replaceBeforeLast( str, 'p b', 'foo', 6 );
+* // returns 'foop boop baz'
+*/
+function replaceBeforeLast( str, search, replacement, fromIndex ) {
+	var idx;
+	if ( fromIndex < 0 ) {
+		return str;
+	}
+	idx = str.lastIndexOf( search, fromIndex );
+	if ( str === '' || search === '' || replacement === '' || idx < 0 ) {
+		return str;
+	}
+	return replacement + str.substring( idx );
+}
+
+
+// EXPORTS //
+
+module.exports = replaceBeforeLast;
diff --git a/base/replace-before-last/package.json b/base/replace-before-last/package.json
new file mode 100644
index 00000000..ed5cd1dd
--- /dev/null
+++ b/base/replace-before-last/package.json
@@ -0,0 +1,69 @@
+{
+  "name": "@stdlib/string/base/replace-before-last",
+  "version": "0.0.0",
+  "description": "Replace the substring before the last occurrence of a specified search string.",
+  "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",
+    "stdstring",
+    "utilities",
+    "utility",
+    "utils",
+    "util",
+    "base",
+    "string",
+    "str",
+    "replace",
+    "search",
+    "substring",
+    "substr",
+    "before",
+    "last",
+    "match"
+  ]
+}
diff --git a/base/replace-before-last/test/test.js b/base/replace-before-last/test/test.js
new file mode 100644
index 00000000..d36115b6
--- /dev/null
+++ b/base/replace-before-last/test/test.js
@@ -0,0 +1,138 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 replaceBeforeLast = require( './../lib' );
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+	t.ok( true, __filename );
+	t.strictEqual( typeof replaceBeforeLast, 'function', 'main export is a function' );
+	t.end();
+});
+
+tape( 'the function replaces the substring before the last occurrence of a specified search string', function test( t ) {
+	var expected;
+	var actual;
+	var str;
+
+	str = 'beep boop';
+	actual = replaceBeforeLast( str, ' ', 'foo', str.length );
+	expected = 'foo boop';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	str = 'beep boop';
+	actual = replaceBeforeLast( str, 'p', 'foo', str.length );
+	expected = 'foop';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	str = 'Hello, World!';
+	actual = replaceBeforeLast( str, 'o', 'foo', str.length );
+	expected = 'fooorld!';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function replaces the substring before the last occurrence of a specified search string (Unicode characters)', function test( t ) {
+	var expected;
+	var actual;
+	var str;
+
+	str = 'beep 😀 boop 😀 baz';
+	actual = replaceBeforeLast( str, '😀', 'foo', str.length );
+	expected = 'foo😀 baz';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	str = '🤖 Robot army 🤖!';
+	actual = replaceBeforeLast( str, '🤖', 'foo', str.length );
+	expected = 'foo🤖!';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	str = '🐺 Wolf brothers 🐺';
+	actual = replaceBeforeLast( str, 'o', 'foo', str.length );
+	expected = 'fooothers 🐺';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function replaces the substring before a provided search string (custom start index)', function test( t ) {
+	var expected;
+	var actual;
+	var str;
+
+	str = 'beep boop baz';
+	actual = replaceBeforeLast( str, ' ', 'foo', 9 );
+	expected = 'foo baz';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	str = 'beep boop baz';
+	actual = replaceBeforeLast( str, 'p', 'foo', 6 );
+	expected = 'foop boop baz';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	str = 'beep boop baz';
+	actual = replaceBeforeLast( str, 'beep', 'foo', -2 );
+	expected = 'beep boop baz';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	str = 'beep boop baz';
+	actual = replaceBeforeLast( str, 'beep', 'foo', 20 );
+	expected = 'foobeep boop baz';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function returns the entire string if the search string is not found', function test( t ) {
+	var expected;
+	var actual;
+	var str;
+
+	str = 'beep boop';
+	actual = replaceBeforeLast( str, 'z', 'foo', str.length );
+	expected = 'beep boop';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	str = 'beep boop';
+	actual = replaceBeforeLast( str, 'baz', 'foo', str.length );
+	expected = 'beep boop';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function returns the entire string if the search string is the empty string', function test( t ) {
+	var expected;
+	var actual;
+	var str;
+
+	str = 'beep boop';
+	actual = replaceBeforeLast( str, '', 'foo', str.length );
+	expected = 'beep boop';
+	t.strictEqual( actual, expected, 'returns expected value' );
+
+	t.end();
+});