stevezhu / vitest-iterator

Additional vitest matchers for iterators and generators.

vitest-iterator

Additional vitest matchers for iterators and generators.

Installation

Pnpm: pnpm i -D vitest-iterator

Yarn: yarn add -D vitest-iterator

Npm: npm i -D vitest-iterator

Setup

Add to vitest.config.ts

import { defineConfig } from 'vitest/config';

export default defineConfig({
  // ...
  test: {
    setupFiles: ['vitest-iterator'],
  },
});

TypeScript

Add a .d.ts file with the following triple-slash directive:

/// <reference types="vitest-iterator/assertion" />

Alternatively, add a types entry in compilerOptions:

{
  "compilerOptions": {
    "types": ["vitest-iterator/assertion"]
  }
}

Usage

test('counts to three', () => {
  const iterator = [0, 1, 2].values();
  expect(iterator).next.toBe(0);
  expect(iterator).next.toBe(1);
  expect(iterator).next.toBe(2);
  expect(iterator).next.toBeDone();
});

.toBeDone() can be used on IteratorResult directly.

test('counts', () => {
  const iterator = [1, 2, 3].values();
  const result = iterator.next();
  expect(result).toHaveProperty('value', 0);
  expect(result).not.toBeDone();
});

This can be used to test generators as well since they implement the iterator protocol.

function* exampleGenerator() {
  yield 1;
}

test('testing generator', () => {
  const iterator = exampleGenerator();
  expect(iterator).next.toBe(1);
  expect(iterator).next.toBeDone();
});

API

.next

Also under the alias: .yields.

Use the .next modifier to unwrap the value in the IteratorResult so that any other matcher can be chained. This can be called with generators as well since they implement the iterator protocol.

Calling expect(iterator).next.toBe() is equivalent to expect(iterator.next().value).toBe().

test('count to three', () => {
  const iterator = [0, 1, 2].values();
  expect(iterator).next.toBe(0);
  expect(iterator).next.toBe(1);
  expect(iterator).next.toBe(2);
});

Since this modifier calls .next() on the iterator, call .next() manually instead if you want to use the result for the same iteration in any other matchers.

test('count to three', () => {
  const iterator = [0, 1, 2].values();
  const result = iterator.next();
  expect(result).toHaveProperty('value', 0);
  expect(result).not.toBeDone();
});

---

.toBeDone()

Use .toBeDone() to check whether an iterator is done.

test('count is done', () => {
  const iterator = [0].values();
  expect(iterator).next.not.toBeDone(); // 0 is consumed here
  expect(iterator).next.toBeDone();
});

The IteratorResult can also be passed directly into the matcher.

test('count is not done', () => {
  const iterator = [0].values();
  expect(iterator.next()).not.toBeDone();
});

vitest-iterator's Issues

Dependency Dashboard

This issue lists Renovate updates and detected dependencies. Read the Dependency Dashboard docs to learn more.

Rate-Limited

These updates are currently rate-limited. Click on a checkbox below to force their creation now.

• Update dependency prettier to v3.3.3
• Update dependency tsup to v8.2.4
• Update pnpm to v9
• Update typescript-eslint monorepo to v8 (major) (@typescript-eslint/eslint-plugin, @typescript-eslint/parser)
• Update vitest monorepo to v2 (major) (@vitest/coverage-v8, @vitest/ui)
• 🔐 Create all rate-limited PRs at once 🔐

Open

These updates have all been created already. Click a checkbox below to force a retry/rebase of any.

• Update dependency @types/chai to v4.3.17
• Update pnpm to v8.15.9
• Update dependency @sinclair/typebox to ^0.33.0
• Update dependency @types/node to v20.14.15
• Update dependency eslint-plugin-simple-import-sort to v12.1.1
• Update dependency prettier-plugin-packagejson to v2.5.1
• Update dependency typescript to v5.5.4
• Update typescript-eslint monorepo to v7.18.0 (@typescript-eslint/eslint-plugin, @typescript-eslint/parser)
• Update vitest monorepo to v1.6.0 (@vitest/coverage-v8, @vitest/ui)
• Update dependency eslint to v9
• Click on this checkbox to rebase all open PRs at once

Detected dependencies

github-actions

.github/workflows/ci.yml

• actions/checkout v4
• pnpm/action-setup v2
• actions/setup-node v4

npm

package.json

• @sinclair/typebox ^0.32.15
• @trivago/prettier-plugin-sort-imports ^4.3.0
• @types/chai ^4.3.12
• @types/node ^20.11.27
• @typescript-eslint/eslint-plugin ^7.2.0
• @typescript-eslint/parser ^7.2.0
• @vitest/coverage-v8 ^1.3.1
• @vitest/ui ^1.3.1
• eslint ^8.57.0
• eslint-config-prettier ^9.1.0
• eslint-plugin-import ^2.29.1
• eslint-plugin-simple-import-sort ^12.0.0
• nps ^5.10.0
• nps-utils ^1.7.0
• prettier ^3.2.5
• prettier-plugin-packagejson ^2.4.12
• tsup ^8.0.2
• typescript ^5.4.2
• vitest >=0.31.0
• node >=16
• pnpm 8.15.4

---

• Check this box to trigger a request for Renovate to run again on this repository

Convert iterator schema to use typebox codegen

https://github.com/sinclairzx81/typebox-codegen