[node.js] chai test array equality doesn't work as expected

Why does the following fail?

expect([0,0]).to.equal([0,0]);

and what is the right way to test that?

Try to use deep Equal. It will compare nested arrays as well as nested Json.

expect({ foo: 'bar' }).to.deep.equal({ foo: 'bar' });

Please refer to main documentation site.

This is how to use chai to deeply test associative arrays.

I had an issue trying to assert that two associative arrays were equal. I know that these shouldn't really be used in javascript but I was writing unit tests around legacy code which returns a reference to an associative array. :-)

I did it by defining the variable as an object (not array) prior to my function call:

var myAssocArray = {};   // not []
var expectedAssocArray = {};  // not []

expectedAssocArray['myKey'] = 'something';
expectedAssocArray['differentKey'] = 'something else';

// legacy function which returns associate array reference
myFunction(myAssocArray);

assert.deepEqual(myAssocArray, expectedAssocArray,'compare two associative arrays');

import chai from 'chai';
const arr1 = [2, 1];
const arr2 = [2, 1];
chai.expect(arr1).to.eql(arr2); // Will pass. `eql` is data compare instead of object compare.

You can use .deepEqual()

const { assert } = require('chai');

assert.deepEqual([0,0], [0,0]);