No unused expressions in mocha chai unit test using standardJS

Question

I am using standardJS for testing my code. Also I am using mocha chai. With that I'm getting the error expect an assignment or function call and instead saw an expression. for this line:

expect(err).to.be.null

But this line is correct, so what am I doing wrong?

Answer 1

Here are two possible solutions:

1. Use dirty-chai

Using dirty-chai you can change this:

expect(err).to.be.null

to this:

expect(err).to.be.null()

Use it like this:

var chai = require('chai');
var dirtyChai = require('dirty-chai');
var expect = chai.expect

chai.use(dirtyChai);

expect(err).to.be.null()

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2. Disable the rule by adding a comment to the top of each test file

/* eslint-disable no-unused-expressions */

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Note: Please read this comment for more information.