Test if a value is a number having a safe integer value.
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> Test if a value is a number having a safe integer value.
``bash`
npm install @stdlib/assert-is-safe-integer
`javascript`
var isSafeInteger = require( '@stdlib/assert-is-safe-integer' );
#### isSafeInteger( value )
Tests if a value is a number having a safe integer value.
`javascript
var Number = require( '@stdlib/number-ctor' );
var bool = isSafeInteger( 5.0 );
// returns true
bool = isSafeInteger( new Number( 5.0 ) );
// returns true
bool = isSafeInteger( 2.0e200 );
// returns false
bool = isSafeInteger( -3.14 );
// returns false
bool = isSafeInteger( null );
// returns false
`
#### isSafeInteger.isPrimitive( value )
Tests if a value is a primitive number having a safe integer value.
`javascript
var Number = require( '@stdlib/number-ctor' );
var bool = isSafeInteger.isPrimitive( -3.0 );
// returns true
bool = isSafeInteger.isPrimitive( new Number( -3.0 ) );
// returns false
`
#### isSafeInteger.isObject( value )
Tests if a value is a Number object having a safe integer value.
`javascript
var Number = require( '@stdlib/number-ctor' );
var bool = isSafeInteger.isObject( 3.0 );
// returns false
bool = isSafeInteger.isObject( new Number( 3.0 ) );
// returns true
`
- An integer valued number is "safe" when the number can be exactly represented as a [double-precision floating-point number][ieee754]. For example,
`javascript
var MAX_SAFE_INTEGER = require( '@stdlib/constants-float64-max-safe-integer' );
// returns 9007199254740991
var x = 9007199254740992;
// returns 9007199254740992
var y = 9007199254740993;
// returns 9007199254740992
var bool = ( x === y );
// returns true
`
In this example, x and y should be distinct, but they are not due to constraints imposed by storing numeric values in [double-precision floating-point format][ieee754]. "Safe" integers are thus [double-precision floating-point numbers][ieee754] having integer values with unequivocal binary representations.
`javascript
var Number = require( '@stdlib/number-ctor' );
var isSafeInteger = require( '@stdlib/assert-is-safe-integer' );
var bool = isSafeInteger( -5.0 );
// returns true
bool = isSafeInteger( 0.0 );
// returns true
bool = isSafeInteger( new Number( 5.0 ) );
// returns true
bool = isSafeInteger( 2.0e200 );
// returns false
bool = isSafeInteger( 5.256 );
// returns false
bool = isSafeInteger( 1.0/0.0 );
// returns false
bool = isSafeInteger( -1.0/0.0 );
// returns false
bool = isSafeInteger( NaN );
// returns false
bool = isSafeInteger( '5' );
// returns false
bool = isSafeInteger( null );
// returns false
`
*
- [@stdlib/assert-is-integer][@stdlib/assert/is-integer]: test if a value is a number having an integer value.
- [@stdlib/assert-is-number][@stdlib/assert/is-number]: test if a value is a number.
*
This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].
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---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/assert-is-safe-integer/tree/deno
[deno-readme]: https://github.com/stdlib-js/assert-is-safe-integer/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/assert-is-safe-integer/tree/umd
[umd-readme]: https://github.com/stdlib-js/assert-is-safe-integer/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/assert-is-safe-integer/tree/esm
[esm-readme]: https://github.com/stdlib-js/assert-is-safe-integer/blob/esm/README.md
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/assert-is-safe-integer/main/LICENSE
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
[@stdlib/assert/is-integer]: https://www.npmjs.com/package/@stdlib/assert-is-integer
[@stdlib/assert/is-number]: https://www.npmjs.com/package/@stdlib/assert-is-number