Creating CLI tools using typescript and ts-node

[IonelLupu]

I am trying to create a CLI tool that will run typescript code instead of Javascript (I really need to run typescript and not transpile the typescript to javascript).
I run the Typescript code by registering the ts-node package manually:

/* index.js */
#!/usr/bin/env node
const path = require('path')

require('ts-node').register({
	transpileOnly : true,
	preferTsExts : true,
})
require('./cli')

/* cli.ts */
const x: number = 123
console.log(x)

/* package.json */
{
  "name": "ionellupu-test-ts-node-cli",
  "main": "index.js",
  "bin": {
    "test-ts-node-cli": "index.js"
  },
  "license": "ISC",
  "dependencies": {
    "ts-node": "^9.1.1",
    "typescript": "^4.2.2"
  }
}

I tested this by installing the package locally using npm link and it works as expected:

$ test-ts-node-cli
123

The problem is when I am installing the CLI tool with npm install -g ionellupu-test-ts-node-cli (after publishing it on npm and running npm unlink) and run it, I get an error:

$ test-ts-node-cli
C:\Users\<username>\AppData\Roaming\npm\node_modules\ionellupu-test-ts-node-cli\cli.ts:1
const x: number = 123
      ^

SyntaxError: Missing initializer in const declaration
    at wrapSafe (internal/modules/cjs/loader.js:979:16)
    ...

This is usually shown when the code is run with the javascript engine instead of the ts-node compiler. This shows that the require('ts-node').register() didn't work for some reason.

I prepared a test package that we can use to reproduce this problem.

One interesting this is that the script does run if I change the directory to the node_modules of the npm:

$ where test-ts-node-cli
C:\Users\<username>\AppData\Roaming\npm\test-ts-node-cli
C:\Users\<username>\AppData\Roaming\npm\test-ts-node-cli.cmd

$ cd C:/Users/<username>/AppData/Roaming/npm/node_modules

$ pwd
/c/Users/<username>/AppData/Roaming/npm/node_modules

$ test-ts-node-cli
123

One other interesting this is that the app works if I run it directly with node from C:\Users\<username>\AppData\Roaming\npm\node_modules:

$ pwd
/c/Users/<username>/AppData/Roaming/npm/node_modules

$ node ionellupu-test-ts-node-cli/index.js
123

But it doens't work if I run it from my home directory:

$ cd ~

$ pwd
/c/Users/<username>

$ node C:/Users/<username>/AppData/Roaming/npm/node_modules/ionellupu-test-ts-node-cli/index.js
C:\Users\<username>\AppData\Roaming\npm\node_modules\ionellupu-test-ts-node-cli\cli.ts:1
const x: number = 123
      ^

SyntaxError: Missing initializer in const declaration

It is really strange that in some cases it works and is others not.

Why is this happening and how can it be solved?
Why isn't ts-node.register working properly when installing the package globally but works when using npm link?

[cspotcode]

At first glance, this might be caused by the default "ignore" option, which is documented in our readme. It could be that the file is located at a path which is ignored, so we do not attempt to transform it.

…

On Thu, Mar 4, 2021, 5:15 PM Ionel lupu ***@***.***> wrote: I am trying to create a CLI tool that will run typescript code instead of Javascript (I really need to run typescript and not transpile the typescript to javascript). I run the Typescript code by registering the ts-node package manually: /* index.js */ #!/usr/bin/env nodeconst path = require('path') require('ts-node').register({ transpileOnly : true, preferTsExts : true,})require('./cli') /* cli.ts */const x: number = 123console.log(x) /* package.json */ { "name": "ionellupu-test-ts-node-cli", "main": "index.js", "bin": { "test-ts-node-cli": "index.js" }, "license": "ISC", "dependencies": { "ts-node": "^9.1.1", "typescript": "^4.2.2" } } I tested this by installing the package locally using npm link and it works as expected: $ test-ts-node-cli 123 The problem is when I am installing the CLI tool with npm install -g ionellupu-test-ts-node-cli (after publishing it on npm and running npm unlink) and run it, I get an error: $ test-ts-node-cli C:\Users\<username>\AppData\Roaming\npm\node_modules\ionellupu-test-ts-node-cli\cli.ts:1 const x: number = 123 ^ SyntaxError: Missing initializer in const declaration at wrapSafe (internal/modules/cjs/loader.js:979:16) ... This is usually shown when the code is run with the javascript engine instead of the ts-node compiler. This shows that the require('ts-node').register() didn't work for some reason. I prepared a test package <https://www.npmjs.com/package/ionellupu-test-ts-node-cli> that we can use to reproduce this problem. One interesting this is that the script does run if I change the directory to the node_modules of the npm: $ where test-ts-node-cli C:\Users\<username>\AppData\Roaming\npm\test-ts-node-cli C:\Users\<username>\AppData\Roaming\npm\test-ts-node-cli.cmd $ cd C:/Users/<username>/AppData/Roaming/npm/node_modules $ pwd /c/Users/<username>/AppData/Roaming/npm/node_modules $ test-ts-node-cli 123 One other interesting this is that the app works if I run it directly with node from C:\Users\<username>\AppData\Roaming\npm\node_modules: $ pwd /c/Users/<username>/AppData/Roaming/npm/node_modules $ node ionellupu-test-ts-node-cli/index.js 123 But it doens't work if I run it from my home directory: $ cd ~ $ pwd /c/Users/<username> $ node C:/Users/<username>/AppData/Roaming/npm/node_modules/ionellupu-test-ts-node-cli/index.js C:\Users\<username>\AppData\Roaming\npm\node_modules\ionellupu-test-ts-node-cli\cli.ts:1 const x: number = 123 ^ SyntaxError: Missing initializer in const declaration It is really strange that in some cases it works and is others not. Why is this happening and how can it be solved? Why isn't ts-node.register working properly when installing the package globally but works when using npm link? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1267>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAC35OFFGVNJM2TVV56AHDDTCABA7ANCNFSM4YUCRG5A> .

[IonelLupu]

I am not using the ignore option directly using skip-ignore should fix the issue?:

require('ts-node').register({
    transpileOnly : true,
    preferTsExts : true,
    skipIgnore: true,
})

[IonelLupu]

You, my friend, are a GOD. May the spirits be with you forever.

OMG, you just saved me 16 hours of painful debugging.

THANK YOU!!!! ❤️

---

So, the ignore option ignores node_modules by default so I guess it doesn't get to require ts-node in the first place. Shouldn't we get an error instead? Something like Could not require 'ts-node' or better Cannot call '.require' of undefined since it doesn't load ts-node.

I am thinking the app shouldn't load if the required packages don't load, right? Should I open a bug?

[cspotcode]

ignore means it will not transform those files. They will still be executed by node.

In general, node_modules should be precompiled, which means that transformation is not required.

[IonelLupu]

I see. Interesting. Thank you once again.

I believe in a world where we will be writing Typescript and run it without transpilation to Javascript. Waiting for that moment. Long time to wait :( Maybe someone will build a V8 for Typescript directly which should be a lot faster (due to known types). Who knows.

PS: The CLI I am building is for Typetron, the Node (soon Deno as well) web framework.