fn is not a function

I’ve simple test that is as follows

// abc.test.ts
const Client = require('node-rest-client').Client;
import Nightmare from "nightmare";
import * as chai from "chai";
import chaiString from "chai-string";
chai.use(chaiString);  
//node_modules\chai\lib\chai.js:39
//    fn(exports, util);
//   ^
// TypeError: fn is not a function

The npm command is as follows mocha --recursive --require jsdom-global/register --require ts-node/register --require babel-core/register tests/domains/*

Issue Analytics

State:
Created 6 years ago
Comments:6 (1 by maintainers)

Top GitHub Comments

23reactions

basherrcommented, Jan 9, 2018

closing as chai works with require statement.

10reactions

meebercommented, Feb 10, 2018

@gary1410 It’s difficult to troubleshoot OP’s issue because they’re using a couple of transpilers. What I can tell you is that “TypeError: fn is not a function” is saying that the value being passed to chai.use() isn’t a function, suggesting that the problem is related to import chaiString from "chai-string"; (as opposed to the Chai import). However, the below example (with no transpilers) works fine for me when running node --experimental-modules with Chai@4.1.2, so I dunno. I’d guess OP’s issue is related to transpiling.

import chai from "chai";
import chaiString from "chai-string";

chai.use(chaiString);

chai.expect("blah").to.startWith("bl"); // Passes
chai.expect("blah").to.startWith("xl"); // Throws AssertionError