245 lines
6.5 KiB
Markdown
245 lines
6.5 KiB
Markdown
<!--
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@license Apache-2.0
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Copyright (c) 2018 The Stdlib Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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# fromCodePoint
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> Create a string from a sequence of Unicode [code points][code-point].
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<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
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<section class="intro">
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</section>
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<!-- /.intro -->
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<!-- Package usage documentation. -->
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<section class="usage">
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## Usage
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```javascript
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var fromCodePoint = require( '@stdlib/string/from-code-point' );
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```
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#### fromCodePoint( pt1\[, pt2\[, pt3\[, ...]]] )
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Creates a `string` from a sequence of Unicode [code points][code-point].
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```javascript
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var out = fromCodePoint( 9731 );
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// returns '☃'
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```
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In addition to providing [code points][code-point] as separate arguments, the function supports providing an array-like `object` as a single argument containing a sequence of [code points][code-point].
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```javascript
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var Uint16Array = require( '@stdlib/array/uint16' );
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var out = fromCodePoint( 97, 98, 99 );
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// returns 'abc'
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out = fromCodePoint( new Uint16Array( [ 97, 98, 99 ] ) );
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// returns 'abc'
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```
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</section>
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<!-- /.usage -->
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<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="notes">
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## Notes
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- This function differs from [`String.fromCharCode`][mdn-string-fromcharcode] in the following ways:
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- The function provides support for all valid Unicode values (up to `21` bits). While most common Unicode values can be represented using one 16-bit unit, higher code point characters require two 16-bit units (a surrogate pair consisting of a high and a low surrogate) to form a single character. [`String.fromCharCode`][mdn-string-fromcharcode] does **not** support surrogate pairs, supporting only UCS-2, a subset of [UTF-16][utf-16].
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- This function differs from [`String.fromCodePoint`][mdn-string-fromcodepoint] in the following ways:
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- The function supports explicitly providing an array-like `object` containing a sequence of [code points][code-point].
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- The function requires **at least** one [code point][code-point].
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- The function requires that all [code points][code-point] be nonnegative integers. The function does **not** support values, such as `null`, `undefined`, `true`, `false`, `'0'`, `'1'`, etc., which can be cast to integer values.
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</section>
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<!-- /.notes -->
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<!-- Package usage examples. -->
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<section class="examples">
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## Examples
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<!-- eslint no-undef: "error" -->
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```javascript
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var randu = require( '@stdlib/random/base/randu' );
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var floor = require( '@stdlib/math/base/special/floor' );
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var UNICODE_MAX_BMP = require( '@stdlib/constants/unicode/max-bmp' );
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var fromCodePoint = require( '@stdlib/string/from-code-point' );
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var x;
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var i;
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for ( i = 0; i < 100; i++ ) {
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x = floor( randu()*UNICODE_MAX_BMP );
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console.log( '%d => %s', x, fromCodePoint( x ) );
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}
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```
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</section>
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<!-- /.examples -->
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<!-- Section for describing a command-line interface. -->
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* * *
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<section class="cli">
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## CLI
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<!-- CLI usage documentation. -->
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<section class="usage">
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### Usage
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```text
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Usage: from-code-point [options] [<code_point> <code_point> ...]
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Options:
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-h, --help Print this message.
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-V, --version Print the package version.
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--split sep Delimiter for stdin data. Default: '/\\r?\\n/'.
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```
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</section>
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<!-- /.usage -->
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<!-- CLI usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="notes">
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### Notes
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- If the split separator is a [regular expression][mdn-regexp], ensure that the `split` option is either properly escaped or enclosed in quotes.
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```bash
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# Not escaped...
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$ echo -n $'97\n98\n99' | from-code-point --split /\r?\n/
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# Escaped...
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$ echo -n $'97\n98\n99' | from-code-point --split /\\r?\\n/
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```
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- The implementation ignores trailing delimiters.
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</section>
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<!-- /.notes -->
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<!-- CLI usage examples. -->
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<section class="examples">
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### Examples
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```bash
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$ from-code-point 9731
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☃
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```
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To use as a [standard stream][standard-streams],
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```bash
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$ echo -n '9731' | from-code-point
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☃
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```
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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.
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```bash
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$ echo -n '97\t98\t99\t' | from-code-point --split '\t'
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abc
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```
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</section>
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<!-- /.examples -->
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</section>
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<!-- /.cli -->
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<!-- 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. -->
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<section class="references">
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</section>
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<!-- /.references -->
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<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
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<section class="related">
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* * *
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## See Also
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- <span class="package-name">[`@stdlib/string/code-point-at`][@stdlib/string/code-point-at]</span><span class="delimiter">: </span><span class="description">return a Unicode code point from a string at a specified position.</span>
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</section>
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<!-- /.related -->
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<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="links">
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[code-point]: https://en.wikipedia.org/wiki/Code_point
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[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams
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[mdn-regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
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[mdn-string-fromcharcode]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCharCode
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[mdn-string-fromcodepoint]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCodePoint
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[utf-16]: https://en.wikipedia.org/wiki/UTF-16
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<!-- <related-links> -->
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[@stdlib/string/code-point-at]: https://github.com/stdlib-js/string/tree/main/code-point-at
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<!-- </related-links> -->
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</section>
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<!-- /.links -->
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