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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 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.
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.
var Number = require( '@stdlib/number/ctor' );
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/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
andy
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 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