Chai Things

Chai Things adds support to Chai for assertions on array elements.

Examples

Something

Use the something property on an array to test whether the assertion holds for one of its elements.

// Although they are equal, two different { a: 'cat' } objects are not the same
[{ a: 'cat' }, { a: 'dog' }].should.not.include({ a: 'cat' })
// Chai Things allows us to test deep equality on one of the elements
[{ a: 'cat' }, { a: 'dog' }].should.include.something.that.deep.equals({ a: 'cat' })
// If the test fails, we get a descriptive message
[{ a: 'cat' }, { a: 'dog' }].should.include.something.that.deep.equals({ a: 'cow' })
/* expected an element of [ { a: 'cat' }, { a: 'dog' } ] to deeply equal { a: 'cow' } */

You are free to choose the syntactic variant you like most:

[4, 11, 15].should.include.one.below(10)
[4, 11, 15].should.contain.some.above(10)
[4, 11, 15].should.not.contain.any.above(20)
[{ a: 'cat' }, { a: 'dog' }].should.contain.a.thing.with.property('a', 'cat')
[{ a: 'cat' }, { a: 'dog' }].should.contain.an.item.with.property('a', 'dog')

All

Use the all property on an array to test whether the assertion holds for all its elements.

// All items are below 20
[4, 11, 15].should.all.be.below(20)
// All items have a property 'a'
[{ a: 'cat' }, { a: 'dog' }].should.all.have.property('a')
// If the test fails, we get a descriptive message
[4, 11, 15].should.all.be.above(20)
/* expected all elements of [ 4, 11, 15 ] to be above 20 */
[{ a: 'cat' }, { a: 'dog' }].should.all.have.property('a', 'cat')
/* expected all elements of [ { a: 'cat' }, { a: 'dog' } ] to have a property 'a' of 'cat', but got 'dog' */

There are currently no syntactic variants for all. Let me know if you need them.

Installation and usage

$ npm install chai-things

var chai = require("chai");
chai.should();
chai.use(require('chai-things'));

Known issues

Because of how Chai works internally, it is not possible to combine Chai Things in certain ways. (See #4 and #9.)