145 lines
2.9 KiB
Markdown
145 lines
2.9 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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# doWhile
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> Invoke a function while a test condition is true.
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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 doWhile = require( '@stdlib/utils/do-while' );
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```
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#### doWhile( fcn, predicate\[, thisArg ] )
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Invokes a `function` until a `predicate` function returns `false`. Note that the `predicate` function is evaluated **after** executing `fcn`; thus, `fcn` **always** executes at least once.
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```javascript
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function predicate( i ) {
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return ( i < 5 );
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}
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function beep( i ) {
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console.log( 'boop: %d', i );
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}
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doWhile( beep, predicate );
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/* =>
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boop: 0
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boop: 1
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boop: 2
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boop: 3
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boop: 4
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*/
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```
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Both the `predicate` function and the `function` to invoke are provided a single argument:
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- `i`: iteration number (starting from zero)
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To set the function execution context for the invoked function, provide a `thisArg`.
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```javascript
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function predicate( i ) {
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return ( i < 5 );
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}
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function count() {
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this.count += 1;
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}
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var context = {
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'count': 0
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};
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doWhile( count, predicate, context );
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console.log( context.count );
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// => 5
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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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</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 doWhile = require( '@stdlib/utils/do-while' );
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function predicate() {
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return ( randu() > 0.05 );
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}
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function log( i ) {
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console.log( i );
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}
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doWhile( log, predicate );
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```
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</section>
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<!-- /.examples -->
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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 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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</section>
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<!-- /.links -->
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