Chai

Chai has several interfaces that allow the developer to choose the most comfortable. The chain-capable BDD styles provide an expressive language & readable style, while the TDD assert style provides a more classical feel.

Should

chai.should();

foo.should.be.a('string');
foo.should.equal('bar');
foo.should.have.lengthOf(3);
tea.should.have.property('flavors')
  .with.lengthOf(3);

Visit Should Guide →

Expect

var expect = chai.expect;

expect(foo).to.be.a('string');
expect(foo).to.equal('bar');
expect(foo).to.have.lengthOf(3);
expect(tea).to.have.property('flavors')
  .with.lengthOf(3);

Visit Expect Guide →

Assert

var assert = chai.assert;

assert.typeOf(foo, 'string');
assert.equal(foo, 'bar');
assert.lengthOf(foo, 3)
assert.property(tea, 'flavors');
assert.lengthOf(tea.flavors, 3);

Visit Assert Guide →

Plugins extend Chai's assertions to new contexts such as vendor integration & object construction. Developers can build their own plugins to share with community or use the plugin pattern to DRY up existing tests.

chai-webdriver

Learn More & Install →

Featured Plugin

Create expressive integration tests with chai and selenium-webdriver.

                chai.use(chaiWebdriver(driver));
driver.get('http://chaijs.com/');
expect('nav h1').dom.to.contain.text('Chai');
expect('#node .button').dom.to.have.style('float', 'left');

Custom Plugins

Browse our growing directory of custom plugins & vendor integrations to find the best tool for your needs.

Browse Plugins→

Develop Plugins

Chai has an extensive utility belt for plugin developers. Learn how to build your plugins & share.

Plugin Guide→

Powered by Open Source

Chai is hosted on GitHub. Have a suggestion or found a bug? Fork this project to help make Chai even better. Even this documentation site is open source and available for contribution.

Fork Chai on GitHub→

Join our Community

We have an active mailing list available at our Google Group, or drop by freenode IRC #chaijs channel to get help anytime.

Visit Google Group→

Download Chai v5.2.0

for Node Another platform? Browser Rails

for Browser Another platform? Node Rails

for Rails Another platform? Node Browser

Chai has several interfaces that allow the developer to choose the most comfortable. The chain-capable BDD styles provide an expressive language & readable style, while the TDD assert style provides a more classical feel.

Should

`chai.should(); foo.should.be.a('string'); foo.should.equal('bar'); foo.should.have.lengthOf(3); tea.should.have.property('flavors') .with.lengthOf(3);`

Visit Should Guide →

Expect

`var expect = chai.expect; expect(foo).to.be.a('string'); expect(foo).to.equal('bar'); expect(foo).to.have.lengthOf(3); expect(tea).to.have.property('flavors') .with.lengthOf(3);`

Visit Expect Guide →

Assert

`var assert = chai.assert; assert.typeOf(foo, 'string'); assert.equal(foo, 'bar'); assert.lengthOf(foo, 3) assert.property(tea, 'flavors'); assert.lengthOf(tea.flavors, 3);`

Visit Assert Guide →

Plugins extend Chai's assertions to new contexts such as vendor integration & object construction. Developers can build their own plugins to share with community or use the plugin pattern to DRY up existing tests.

chai-webdriver

Featured Plugin

Custom Plugins

Develop Plugins

Powered by Open Source

Join our Community

Chai has several interfaces that allow the developer to choose the most comfortable. The chain-capable BDD styles provide an expressive language & readable style, while the TDD assert style provides a more classical feel.

Should chai.should(); foo.should.be.a('string'); foo.should.equal('bar'); foo.should.have.lengthOf(3); tea.should.have.property('flavors') .with.lengthOf(3); Visit Should Guide →

Expect var expect = chai.expect; expect(foo).to.be.a('string'); expect(foo).to.equal('bar'); expect(foo).to.have.lengthOf(3); expect(tea).to.have.property('flavors') .with.lengthOf(3); Visit Expect Guide →

Assert var assert = chai.assert; assert.typeOf(foo, 'string'); assert.equal(foo, 'bar'); assert.lengthOf(foo, 3) assert.property(tea, 'flavors'); assert.lengthOf(tea.flavors, 3); Visit Assert Guide →

Plugins extend Chai's assertions to new contexts such as vendor integration & object construction. Developers can build their own plugins to share with community or use the plugin pattern to DRY up existing tests.

chai-webdriver

Featured Plugin

Custom Plugins

Develop Plugins

Powered by Open Source

Join our Community

Should

`chai.should(); foo.should.be.a('string'); foo.should.equal('bar'); foo.should.have.lengthOf(3); tea.should.have.property('flavors') .with.lengthOf(3);`

Visit Should Guide →

Expect

`var expect = chai.expect; expect(foo).to.be.a('string'); expect(foo).to.equal('bar'); expect(foo).to.have.lengthOf(3); expect(tea).to.have.property('flavors') .with.lengthOf(3);`

Visit Expect Guide →

Assert

`var assert = chai.assert; assert.typeOf(foo, 'string'); assert.equal(foo, 'bar'); assert.lengthOf(foo, 3) assert.property(tea, 'flavors'); assert.lengthOf(tea.flavors, 3);`

Visit Assert Guide →