assertTrue - API reference

API reference › @evolu/common › Assert › assertTrue

Call Signature

function assertTrue(condition: boolean): asserts condition;

Defined in: packages/common/src/Assert.ts:191

Asserts that a value is exactly true.

Boolean conditions preserve their control-flow narrowing, including named type guards. Unknown values narrow to the literal true. Unlike assert, this checks an exact boolean value instead of truthiness and does not require a custom message.

Example

import { assertTrue, assertType } from "@evolu/common";

interface User {
  readonly name: string;
}

const isUser = (value: unknown): value is User =>
  typeof value === "object" &&
  value !== null &&
  "name" in value &&
  typeof value.name === "string";

const value: unknown = { name: "Ada" };
assertTrue(isUser(value));
assertType<typeof value, User>();

const condition: unknown = true;
assertTrue(condition);
assertType<typeof condition, true>();

Call Signature

function assertTrue(value: unknown): asserts value is true;

Defined in: packages/common/src/Assert.ts:192

Asserts that a value is exactly true.

Example

import { assertTrue, assertType } from "@evolu/common";

interface User {
  readonly name: string;
}

const isUser = (value: unknown): value is User =>
  typeof value === "object" &&
  value !== null &&
  "name" in value &&
  typeof value.name === "string";

const value: unknown = { name: "Ada" };
assertTrue(isUser(value));
assertType<typeof value, User>();

const condition: unknown = true;
assertTrue(condition);
assertType<typeof condition, true>();