Overriding `tsconfig.json` for ts-node in mocha

Question

Is it possible to override which tsconfig.json ts-node uses when called from mocha?

My main tsconfig.json contains \"module\": \"es20

Answer 1

--compilerOptions wont' work.

What you need to do is customize how you register ts-node. My case was a little bit different from yours, I wanted it to use test/tsconfig.json, which contained settings needed by my test code. If I just used --require ts-node/register, it was using a default configuration that did not contain the settings needed to run my tests.

What I did was:

1. Create a file test/tshook.js. It contains:

   require("ts-node").register({
     project: "test/tsconfig.json",
   });
   

2. I edited my test/mocha.opts to have:

   --require test/tshook.js
   test/**/*.ts
   

This should will pass the desired setting to ts-node:

require("ts-node").register({
  compilerOptions: {
    module: "commonjs",
  },
});