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Number.isSafeInteger()
function warn(x) {
if (Number.isSafeInteger(x)) {
return "Precision safe.";
}
return "Precision may be lost!";
}
console.log(warn(Math.pow(2, 53)));
// : "Precision may be lost!"
console.log(warn(Math.pow(2, 53) - 1));
// : "Precision safe."
Number.isSafeInteger(testValue)
true false
-(253 - 1) 253 - 1 (9,007,199,254,740,991)
253 - 1 IEEE-754 253 IEEE-754 253 + 1 IEEE-754 253
~9 What Every Programmer Needs to Know about Floating Point Arithmetic s
Number.isSafeInteger(3); // true
Number.isSafeInteger(2 ** 53); // false
Number.isSafeInteger(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
| ECMAScript 2027 LanguageSpecification # sec-number.issafeinteger |
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