How can I solve "ReferenceError: expect is not defined" error message?
Mocha is a test framework; you need to provide your own assertion lib as https://mochajs.org/#assertions states. Thus, expect
is indeed undefined because you never defined it.
(I recommend chai)
npm install chai
then
(see Amit Choukroune's comment pointing out to actually require chai)
then
var expect = chai.expect;
Try
First, in the terminal
npm install expect.js
And in your code:
var expect = require('expect');
After you install Chai as other posts suggest, with the es6 syntax you should put the import at the top
import {expect} from 'chai';
let chai = require('chai');
var assert = chai.assert;
describe('Array', function() {
describe('#indexOf()', function() {
it('should return -1 when the value is not present', function() {
assert.equal(-1, [1, 2, 3].indexOf(4));
});
});
});