Please note, this is a STATIC archive of website developer.mozilla.org from 03 Nov 2016, cach3.com does not collect or store any user information, there is no "phishing" involved.

이 문서는 아직 자원 봉사자들이 한국어로 번역하지 않았습니다. 함께 해서 번역을 마치도록 도와 주세요!

The Number.isSafeInteger() method determines whether the provided value is a number that is a safe integer. A safe integer is an integer that

  • can be exactly represented as an IEEE-754 double precision number, and
  • whose IEEE-754 representation cannot be the result of rounding any other integer to fit the IEEE-754 representation.

For example, 253 - 1 is a safe integer: it can be exactly represented, and no other integer rounds to it under any IEEE-754 rounding mode. In contrast, 253 is not a safe integer: it can be exactly represented in IEEE-754, but the integer 253 + 1 can't be directly represented in IEEE-754 but instead rounds to 253 under round-to-nearest and round-to-zero rounding.

The safe integers consist of all integers from -(253 - 1) inclusive to 253 - 1 inclusive.

Syntax

Number.isSafeInteger(testValue)

Parameters

testValue
The value to be tested for being a safe integer.

Return value

A Boolean indicating whether or not the given value is a number that is a safe integer.

Examples

Number.isSafeInteger(3);                    // true
Number.isSafeInteger(Math.pow(2, 53));      // false
Number.isSafeInteger(Math.pow(2, 53) - 1);  // true
Number.isSafeInteger(NaN);                  // false
Number.isSafeInteger(Infinity);             // false
Number.isSafeInteger('3');                  // false
Number.isSafeInteger(3.1);                  // false
Number.isSafeInteger(3.0);                  // true

Polyfill

Number.isSafeInteger = Number.isSafeInteger || function (value) {
   return Number.isInteger(value) && Math.abs(value) <= Number.MAX_SAFE_INTEGER;
};

Specifications

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Number.isSafeInteger' in that specification.
Standard Initial definition.
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Number.isSafeInteger' in that specification.
Draft  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) 32 (32) No support (Yes) 10.0
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support 32.0 (32) No support No support No support

See also

문서 태그 및 공헌자

 최종 변경: ocxers,