assertNonEmptyArray - API reference

API reference › @evolu/common › Assert › assertNonEmptyArray

const assertNonEmptyArray: <T>(
  arr: T[],
  message?: string,
) => asserts arr is NonEmptyArray<T>;

Defined in: packages/common/src/Assert.ts:430

Asserts that an array is non-empty.

Use this when an array is logically guaranteed to be non-empty but TypeScript cannot prove it.

Example

import {
  assertEqual,
  assertErr,
  assertNonEmptyArray,
  assertType,
  trySync,
  type NonEmptyArray,
} from "@evolu/common";

const values = [1, 2, 3];
assertNonEmptyArray(values);
assertType<NonEmptyArray<number>, typeof values>();
assertEqual(values[0], 1);
const result = trySync(() => assertNonEmptyArray([]));
assertErr(result);