Match partial objects in Chai assertions?

Question

I am looking for the best way to match the following:

expect([
    {
        C1: \'xxx\',
        C0: \'this causes it not to match.\'
    }
]).to.deep.incl         


        

Answer 1

I believe the simplest (and certainly easiest) way would be to:

var actual=[
  {
    C1:'xxx',
    C0:'yyy'
  }
];

actual.forEach(function(obj){
  expect(obj).to.have.property('C1','xxx');
});

Answer 2

I wrote chai-match-pattern and lodash-match-pattern to handle partial matching (and many more) deep matching scenarios.

var chai = require('chai');
var chaiMatchPattern = require('chai-match-pattern');
chai.use(chaiMatchPattern);

// Using JDON pattern in expectation
chai.expect([
  {
    C1: 'xxx',
    C0: 'this causes it not to match.'
  }
]).to.matchPattern([
  {
    C1: 'xxx',
    '...': ''
  }
]);

// Using the slightly cleaner string pattern notation in expectation
chai.expect([
  {
    C1: 'xxx',
    C0: 'this causes it not to match.'
  }
]).to.matchPattern(`
  [
    {
      C1: 'xxx',
      ...
    }
  ]
  `
);

Answer 3

without plugins: http://chaijs.com/api/bdd/#method_property

  expect([
    {
      C1: 'xxx',
      C0: 'this causes it not to match.'
    }
  ]).to.have.deep.property('[0].C1', 'xxx');

Answer 4

There are a few different chai plugins which all solve this problem. I am a fan of shallow-deep-equal. You'd use it like this:

expect([
    {
      C1: 'xxx',
      C0: 'this causes it not to match.'
    }
  ]).to.shallowDeepEqual([
    {
      C1: 'xxx'
    }
  ]);

Answer 5

You can use pick and omit underscore functions to select/reject properties to test:

const { pick, omit } = require('underscore');

const obj = {
  C1: 'xxx',
  C0: 'this causes it not to match.',
};

it('tests sparse object with pick', () => {
  expect(pick(obj, 'C1')).to.eql({ C1: 'xxx' });
});

it('tests sparse object with omit', () => {
  expect(omit(obj, 'C0')).to.eql({ C1: 'xxx' });
});

Answer 6

Slightly updated version of #RobRaisch because for empty comparison giving error because '' not equal ""

let expected = {
            dateOfBirth: '',
            admissionDate: '',
            dischargeDate: '',
            incidentLocation: null
        };
        Object.keys(expected).forEach(function(key) {
            expect(actual[key]).to.equal(expected[key]);
        });