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last/README.md

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+<!--
+
+@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.
+
+-->
+
+# last
+
+> Return the last character(s) of a string.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var last = require( '@stdlib/string/last' );
+```
+
+#### last( str\[, n]\[, options] )
+
+Returns the last character(s) of a string.
+
+```javascript
+var out = last( 'last man standing' );
+// returns 'g'
+
+out = last( 'Hidden Treasures' );
+// returns 's'
+```
+
+The function supports the following options:
+
+-   **mode**: type of characters to return. Must be one of the following:
+
+    -   `'grapheme'`: grapheme clusters. Appropriate for strings containing visual characters which can span multiple Unicode code points (e.g., emoji).
+    -   `'code_point'`: Unicode code points. Appropriate for strings containing visual characters which are comprised of more than one Unicode code unit (e.g., ideographic symbols and punctuation and mathematical alphanumerics).
+    -   `'code_unit'`: UTF-16 code units. Appropriate for strings containing visual characters drawn from the basic multilingual plane (BMP) (e.g., common characters, such as those from the Latin, Greek, and Cyrillic alphabets).
+
+    Default: `'grapheme'`.
+
+By default, the function returns the last character. To return the last `n` characters, provide a second argument specifying the number of characters to return.
+
+```javascript
+var out = last( 'foo bar', 3 );
+// returns 'bar'
+
+out = last( 'foo bar', 10 );
+// returns 'foo bar'
+```
+
+</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
+
+-   By default, the function assumes the general case in which an input string may contain an arbitrary number of grapheme clusters. This assumption comes with a performance cost. Accordingly, if an input string is known to only contain visual characters of a particular type (e.g., only alphanumeric), one can achieve better performance by specifying the appropriate `mode` option.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var last = require( '@stdlib/string/last' );
+
+var str = last( 'last man standing' );
+// returns 'g'
+
+str = last( 'presidential election' );
+// returns 'n'
+
+str = last( 'javaScript' );
+// returns 't'
+
+str = last( 'Hidden Treasures' );
+// returns 's'
+
+str = last( 'The Last of the Mohicans', 8 );
+// returns 'Mohicans'
+
+str = last( '🐶🐮🐷🐰🐸', 2 );
+// returns '🐰🐸'
+
+str = last( '🐶🐮🐷🐰🐸', 10 );
+// returns '🐶🐮🐷🐰🐸'
+```
+
+</section>
+
+<!-- /.examples -->
+
+* * *
+
+<section class="cli">
+
+## CLI
+
+<section class="usage">
+
+### Usage
+
+```text
+Usage: last [options] [<string>]
+
+Options:
+
+  -h,    --help                Print this message.
+  -V,    --version             Print the package version.
+         --n num               Number of characters to return. Default: 1.
+         --split sep           Delimiter for stdin data. Default: '/\\r?\\n/'.
+         --mode mode           Type of character to return. Default: 'grapheme'.
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- CLI usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+### Notes
+
+-   If the split separator is a [regular expression][mdn-regexp], ensure that the `split` option is either properly escaped or enclosed in quotes.
+
+    ```bash
+    # Not escaped...
+    $ echo -n $'beep\nboop' | last --split /\r?\n/
+
+    # Escaped...
+    $ echo -n $'beep\nboop' | last --split /\\r?\\n/
+    ```
+
+-   The implementation ignores trailing delimiters.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+### Examples
+
+```bash
+$ last beep
+p
+```
+
+To use as a [standard stream][standard-streams],
+
+```bash
+$ echo -n 'beep\nboop' | last --n=2
+ep
+op
+```
+
+By default, when used as a [standard stream][standard-streams], the implementation assumes newline-delimited data. To specify an alternative delimiter, set the `split` option.
+
+```bash
+$ echo -n 'beep\tboop' | last --split '\t'
+p
+p
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.cli -->
+
+<!-- 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">
+
+[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams
+
+[mdn-regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
+
+<!-- <related-links> -->
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->

last/benchmark/benchmark.js

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+/**
+* @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 last = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var values;
+	var out;
+	var i;
+
+	values = [
+		'beep boop',
+		'foo bar',
+		'xyz abc'
+	];
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = last( values[ i%values.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();
+});
+
+bench( pkg+':mode=grapheme', function benchmark( b ) {
+	var values;
+	var opts;
+	var out;
+	var i;
+
+	values = [
+		'beep boop',
+		'foo bar',
+		'xyz abc'
+	];
+	opts = {
+		'mode': 'grapheme'
+	};
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = last( values[ i%values.length ], opts );
+		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();
+});
+
+bench( pkg+':mode=code_point', function benchmark( b ) {
+	var values;
+	var opts;
+	var out;
+	var i;
+
+	values = [
+		'beep boop',
+		'foo bar',
+		'xyz abc'
+	];
+	opts = {
+		'mode': 'code_point'
+	};
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = last( values[ i%values.length ], opts );
+		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();
+});
+
+bench( pkg+':mode=code_unit', function benchmark( b ) {
+	var values;
+	var opts;
+	var out;
+	var i;
+
+	values = [
+		'beep boop',
+		'foo bar',
+		'xyz abc'
+	];
+	opts = {
+		'mode': 'code_unit'
+	};
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = last( values[ i%values.length ], opts );
+		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();
+});