The Number.MAX_SAFE_INTEGER
constant represents the maximum safe integer in JavaScript (253 - 1
).
For larger integers, consider using BigInt
.
Property attributes of Number.MAX_SAFE_INTEGER
| |
---|---|
Writable | no |
Enumerable | no |
Configurable | no |
The MAX_SAFE_INTEGER
constant has a value of 9007199254740991
(9,007,199,254,740,991 or ~9 quadrillion). The reasoning behind that number is that JavaScript uses double-precision floating-point format numbers as specified in IEEE 754 and can only safely represent integers between -(253 - 1)
and 253 - 1
.
Safe in this context refers to the ability to represent integers exactly and to correctly compare them. For example, Number.MAX_SAFE_INTEGER + 1 === Number.MAX_SAFE_INTEGER + 2
will evaluate to true, which is mathematically incorrect. See Number.isSafeInteger()
for more information.
This field does not exist in old browsers. Using it without checking its existence, such as Math.max(Number.MAX_SAFE_INTEGER, 2)
, will yield undesired results such as NaN.
Because MAX_SAFE_INTEGER
is a static property of Number
, you always use it as Number.MAX_SAFE_INTEGER
, rather than as a property of a Number
object you created.
if (!Number.MAX_SAFE_INTEGER) { Number.MAX_SAFE_INTEGER = 9007199254740991; // Math.pow(2, 53) - 1; }
Number.MAX_SAFE_INTEGER; // 9007199254740991
This returns 2 because in floating points, the value is actually the decimal trailing "1" except for in subnormal precision cases such as zero.
Number.MAX_SAFE_INTEGER * Number.EPSILON; // 2
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Number.MAX_SAFE_INTEGER' in that specification. |
Desktop | ||||||
---|---|---|---|---|---|---|
MAX_SAFE_INTEGER |
34 | 12 | 31 | No | 21 | 9 |
Mobile | ||||||
---|---|---|---|---|---|---|
MAX_SAFE_INTEGER |
≤37 | 34 | 31 | 21 | 9 | 2.0 |
Server | |
---|---|
MAX_SAFE_INTEGER |
0.12 |
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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER