'Cannot find module 'ts-node/register'

I want to use mocha to test my TypeScript/Angular2 project. I tried to use ts-node as described here: 

npm install -g ts-node

but when running 

mocha --require ts-node/register -t 10000 ./**/*.unit.ts

I get an error

Cannot find module 'ts-node/register'

What am I missing here?

node.jstypescriptmocha.js


Solution 1:[1]

Since the answer that works for a lot of people appears to be hidden in the comments, I'll post it as an actual answer to the question, now that it appears the question has been reopened.

I had this problem as well. Not sure why this Q has been closed. but installing ts-node locally fixes this. npm install ts-node --save-dev

Thanks @Anita, as this was the answer that worked for me too.

Solution 2:[2]

Wow, a silly mistake can cost you time. I was facing the same issue when I was trying to debug my nodejs application. The mistake I had done was that I have created my .vscode folder outside of my nodejs app folder(the directory which had node_modules in it). When I moved my .vscode to that folder, everything work fine. Below is my launch.json file.

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "index",         
            "args": [
                "src/index.ts"
            ],
            "runtimeArgs": [
                "-r",
                "ts-node/register"
            ],
            "cwd": "${workspaceFolder}",
            "protocol": "inspector",
            "internalConsoleOptions": "openOnSessionStart"           
        }
    ],
    "compounds": []
}

enter image description here

Solution 3:[3]

I know this is kind of old, but I ran into this too and wanted to offer the solution I'm currently using.

I installed ts-node globally using sudo npm i -g ts-node. To make this work with mocha, I just had to give mocha the absolute path to the module, like this:

mocha -r /usr/lib/node_modules/ts-node/register test/*Test.ts

Hope that helps someone else.

Solution 4:[4]

Try this command instead:

mocha --compilers ts:ts-node/register,tsx:ts-node/register

which works for me.

Solution 5:[5]

I have mocha and ts-node installed as dev dependencies in my package. I'm also using pnpm. I originally had a script for test that was defined as:

pnpx mocha -r ts-node/register '*.test.ts'

When this stopped working with the same error as reported in this question I fixed it by making the -r path explicit:

pnpx mocha -r ./node_modules/ts-node/register '*.test.ts'

I'm still confused as to why the original version stopped working.

Solution 6:[6]

Assuming you rather not install ts-node locally and would prefer to use the globally installed node_module. The following examples show what to do for Windows and assumes you're using NVM. If not using NVM, replace NVM_SYMLINK with C:\Program Files\nodejs

Example for command line:

node -r "%NVM_SYMLINK%\node_modules\ts-node\register" script.ts arg1 arg2

Example for bash:

node -r "$NVM_SYMLINK/node_modules/ts-node/register" script.ts arg1 arg2

Example for vscode launch.config

  "configurations": [
    {
      "name": "utils/roll_browser",
      "type": "node",
      "request": "launch",
      "runtimeArgs": [
        "-r",
        /* Slower startup. Runs full typescript validation */
        // "${env:NVM_SYMLINK}/node_modules/ts-node/register"
        /* Faster startup. Doesn't check types or verify the code is valid */
        "${env:NVM_SYMLINK}/node_modules/ts-node/register/transpile-only"
      ],
      "args": ["${workspaceFolder}/utils/roll_browser.ts", "chromium", "756141"],
    },
  ]

Solution 7:[7]

I have the same issue while using "jasmine-unit-test-generator". I fix it by runing npm link ts-node. you can refer to https://github.com/TypeStrong/ts-node/issues/565

Solution 8:[8]

Use /node_modules/ts-node/register in place of ts-node/register. So in your case it'll become:

mocha --require /node_modules/ts-node/register -t 10000 ./**/*.unit.ts

and make sure ts-node is installed locally in your project like:

npm install ts-node @types/node typescript

This solution doesn't need you to install ts-node globally. And it works cross platform and for everyone.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Louie Bertoncin
Solution 2 Sibeesh Venu
Solution 3 kael
Solution 4 Mike Lischke
Solution 5 ironchicken
Solution 6 Derek Ziemba
Solution 7 Emon
Solution 8 lockhrt

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