Run a group of assertions in any Node test framework, keep going past failures, and get one readable error that lists every failure. Works with Jest, Vitest, node:test, mocha/chai, Playwright and anything else that throws on a failed assertion. No runtime dependencies.

npm install --save-dev @funktechno/multi-assert

import { multiAssert } from "@funktechno/multi-assert";

multiAssert([
  () => expect(res.status).toBe(200),
  () => expect(res.body.id).toBe(42),
  () => assert.equal(res.headers["content-type"], "application/json"),
]);

2 of 3 assertions failed

  ✕ 1) expected 404 to be 200 // Object.is equality
       → src/api/__tests__/http.spec.ts:38:24

  ✕ 3) Expected values to be strictly equal:
       + actual - expected
       + 'text/html'
       - 'application/json'
       → src/api/__tests__/http.spec.ts:40:14

// bare functions
multiAssert([() => a(), () => b()]);

// labelled, as tuples or as an object
multiAssert([["status is 200", () => a()], ["has id", () => b()]]);
multiAssert({ "status is 200": () => a(), "has id": () => b() });

// async checks run in order
await multiAssertAsync([async () => expect(await load()).toBe(1), () => b()]);

multiAssert is synchronous. A check that returns a promise is reported as a failure that tells you to use multiAssertAsync, so a rejected promise is never silently dropped.

Set defaults once, for example in a test setup file: configure({ stackFrames: 0 }).

Two or more failures throw a MultiAssertError (an AggregateError):

• errors: the original errors, untouched, so instanceof, actual and expected survive;
• failures: { index, label?, message, actual?, expected?, operator?, location? }[];
• passed and total counts;
• toJSON() returns { name, message, passed, total, failures }. failures, passed and total are non-enumerable so reporters that dump an error's own properties (Vitest) do not print them twice.

The first line of the message is a short summary because JUnit message attributes and CI annotation titles usually show only that. error.stack points at the call to multiAssert, so reporter code frames land in your test.

Built in: expect matcher results (Jest, Vitest, Playwright), node:assert, chai, plain Error and non-Error throws. For an in-house assertion library:

multiAssert(checks, {
  adapters: [
    {
      matches: (e) => e instanceof MyAssertError,
      normalize: (e) => ({ message: (e as MyAssertError).detail }),
    },
  ],
});

import "@funktechno/multi-assert/jest" (or installMultiAssertMatchers(expect)) adds expect(value).toPassAll([...]), where each check receives value:

expect(res).toPassAll([
  ["status", (r) => expect(r.status).toBe(200)],
  ["id", (r) => expect(r.body.id).toBe(42)],
]);

Types for the subpath need moduleResolution node16, nodenext or bundler.

npm ci
npm run lint
npm test
npm run build

MIT