npm package: @stdlib/math-base-assert-is-safe-integer
Description: Test if a finite double-precision floating-point number is a safe integer.
Author: The Stdlib Authors
Latest version: 0.3.2

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# isSafeInteger

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> Test if a finite [double-precision floating-point number][ieee754] is a safe integer.

<section class="installation">

## Installation

```bash
npm install @stdlib/math-base-assert-is-safe-integer
```

</section>

<section class="usage">

## Usage

```javascript
var isSafeInteger = require( '@stdlib/math-base-assert-is-safe-integer' );
```

#### isSafeInteger( x )

Tests if a finite [double-precision floating-point number][ieee754] is a safe integer.

```javascript
var bool = isSafeInteger( 1.0 );
// returns true
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   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.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var isSafeInteger = require( '@stdlib/math-base-assert-is-safe-integer' );

var bool = isSafeInteger( -5.0 );
// returns true

bool = isSafeInteger( 2.0e200 );
// returns false

bool = isSafeInteger( 3.14 );
// returns false

bool = isSafeInteger( NaN );
// returns false
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- C usage documentation. -->

<section class="usage">

### Usage

```c
#include "stdlib/math/base/assert/is_safe_integer.h"
```

#### stdlib_base_is_safe_integer( x )

Tests if a finite [double-precision floating-point number][ieee754] is a safe integer.

```c
#include <stdbool.h>

bool out = stdlib_base_is_safe_integer( 3.0 );
// returns true

out = stdlib_base_is_safe_integer( 2.0e200 );
// returns false
```

The function accepts the following arguments:

-   **x**: `[in] double` input value.

```c
bool stdlib_base_is_safe_integer( const double x );
```

</section>

<!-- /.usage -->

<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

</section>

<!-- /.notes -->

<!-- C API usage examples. -->

<section class="examples">

### Examples

```c
#include "stdlib/math/base/assert/is_safe_integer.h"
#include <stdio.h>
#include <stdbool.h>

int main( void ) {
    const double x[] = { 5.0, -5.0, 3.14, -3.14, 0.0, 0.0/0.0 };

    bool b;
    int i;
    for ( i = 0; i < 6; i++ ) {
        b = stdlib_base_is_safe_integer( x[ i ] );
        printf( "Value: %lf. Is safe integer? %s.\n", x[ i ], ( b ) ? "True" : "False" );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## Notice

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].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

<!-- /.stdlib -->

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[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985

</section>

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