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About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

Boolean

NPM version Build Status Coverage Status

Boolean constructor.

Usage

To use in Observable,

Boolean = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/boolean-ctor@umd/browser.js' )

To vendor stdlib functionality and avoid installing dependency trees for Node.js, you can use the UMD server build:

var Boolean = require( 'path/to/vendor/umd/boolean-ctor/index.js' )

To include the bundle in a webpage,

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/boolean-ctor@umd/browser.js"></script>

If no recognized module system is present, access bundle contents via the global scope:

<script type="text/javascript">
(function () {
    window.Boolean;
})();
</script>

Boolean( value )

Returns a Boolean object, which is an object wrapper for a primitive boolean value.

var b = new Boolean( null );
// returns <Boolean>

When invoked without new, the function converts an input value to a primitive boolean value.

var b = Boolean( null );
// returns false

Methods

Boolean.prototype.toString()

Returns a string representation of the boolean value.

var b = new Boolean( true );
var str = b.toString();
// returns 'true'
Boolean.prototype.valueOf()

Returns the primitive value of the boolean object.

var b = new Boolean( true );
var val = b.valueOf();
// returns true

b = new Boolean();
val = b.valueOf();
// returns false

Notes

  • When invoked without new,

    • if provided false, null, undefined, -0, 0, NaN, or an empty string, the function returns false.
    • if provided any other value, including an empty object, an empty array, the string 'false', or a Boolean object (including a Boolean object whose value is false), the function returns true.

  • When invoked with new, the value of the returned Boolean object adheres to the same conversion semantics as when the constructor is invoked without new.

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/string-format@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/boolean-ctor@umd/browser.js"></script>
<script type="text/javascript">
(function () {

var values = [
    '5',
    5,
    0,
    NaN,
    true,
    false,
    null,
    void 0,
    [],
    {}
];

var i;
for ( i = 0; i < values.length; i++ ) {
    console.log( format( '%s => %s', JSON.stringify( values[ i ] ), ( Bool( values[ i ] ) ) ? 'true' : 'false' ) );
}

})();
</script>
</body>
</html>

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

Chat

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.