isSafeInteger
function isSafeInteger(value: unknown): value is number;
An integer that an IEEE-754 double represents exactly. Beyond that range distinct mathematical integers collapse onto the same value and arithmetic quietly stops being exact.
isX and nonX answer a question and never interrupt control flow; requireX and requireNonX hand the value back or throw. The scheme is explained in Validation conventions.
Parameters
Parameter | Type | Description |
|---|---|---|
|
| The value to check. |
Returns
boolean — true when the value is a safe integer; otherwise false.
In TypeScript the guard narrows value to number inside the branch.
Examples
What passes and what does not
isSafeInteger(42); // => true
isSafeInteger(Number.MAX_SAFE_INTEGER); // => true
isSafeInteger(Number.MAX_SAFE_INTEGER + 2); // => false
isSafeInteger(1.5); // => false
isSafeInteger("42"); // => false
See also
Source
23 September 2026
This documentation was generated with AI (Claude) from the library's source code.