chai-snap

Built on snap-shot-it, chai-snap extends Chai with a fluent assertion API for snapshot testing.

Instead of using snap-shot-it's native assertions:

snapshot('test');

you can just say:

expect('test').to.snapshot();
'test'.should.snapshot();

Features ✨

• Intuitive assertion syntax: expect(value).to.snapshot()
• Simple snapshot testing integration for Chai
• Chainable assertions: Seamlessly combine with other Chai methods
• Type safety
• Compatible with Mocha and other test runners

Installation 📦

npm install chai-snap --save-dev

Usage 🚀

1. Add chai-snap to your test setup:

use(chaiSnap);

2. Use in your tests:

expect('test').to.snapshot();

Or if you prefer should:

'test'.should.snapshot();

NEW in v1.2.0: Snapshots can be named for better test clarity:

expect('test').to.snapshot('test-snapshot');

Basic Example

import { expect, use } from 'chai';
import chaiSnap from 'chai-snap';

// Add snapshot support to Chai
use(chaiSnap);

describe('Snapshot Testing', () => {
  it('should match snapshot', () => {
    expect('test').to.snapshot().and.be.a('string');
  });
});

Updating Snapshots

Set environment variable to update snapshots:

SNAPSHOT_UPDATE=1 npm test

API Documentation 📖

expect(value).to.snapshot(name?)

• value: Any value to compare against stored snapshot
• name: Optional name for the snapshot, generated from the name from the test title and snapshot index if not provided
• Behavior:
  • Creates new snapshot on first run
  • Compares against stored snapshot in subsequent runs
  • Updates snapshot when SNAPSHOT_UPDATE=1 is set