Variable isBigint`Const`

isBigint: (u: unknown) => u is bigint

Type guard that checks if a value is a bigint.

Type Narrowing Behavior:

Narrows unknown to bigint when true
Identifies values created with BigInt() constructor or n suffix

Type Declaration

- (u: unknown): u is bigint
- Parameters
  - u: unknown
    The value to check
  Returns u is bigint
  true if u is a bigint, false otherwise. When true, TypeScript narrows the type to bigint.

Example

const values: readonly unknown[] = [1n, 2, 3n] as const;

const bigints = values.filter(isBigint);

assert.deepStrictEqual(bigints, [1n, 3n]);