isSafeInteger

Test if a value is a number having a safe integer value.

Usage

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

isSafeInteger( value )

Tests if a value is a number having a safe integer value.

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.

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.

var bool = isSafeInteger.isObject( 3.0 );
// returns false

bool = isSafeInteger.isObject( new Number( 3.0 ) );
// returns true

Notes

  • An integer valued number is "safe" when the number can be exactly represented as a double-precision floating-point number. For example,

    var MAX_SAFE_INTEGER = require( '@stdlib/constants/math/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. "Safe" integers are thus double-precision floating-point numbers having integer values with unequivocal binary representations.

Examples

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