How to fix Cannot find module 'typescript' in Angular 4?

Question

I generated Angular 4 app 3 weeks ago using the @angular/cli. After 2 weeks, I tried to run it with the command line \"ng serve\" but I am prompted an error bel

Answer 1

I was able to solve this problem by removing node_modules then running "npm install"

Answer 2

If you don't have particular needs, I suggest to install Typescript locally.

NPM Installation Method

npm install --global typescript # Global installation
npm install --save-dev typescript # Local installation

Yarn Installation Method

yarn global add typescript # Global installation
yarn add --dev typescript # Local installation

Answer 3

This should do the trick,

npm install -g typescript

Answer 4

I had a similar problem when I rearranged the folder structure of a project. I tried all the hints given in this thread but none of them worked. After checking further I discovered that I forgot to copy an important hidden file over to the new directory. That was

.angular-cli.json

from the root directory of the @angular/cli project. After I copied that file over all was running as expected.

Answer 5

Run: npm link typescript if you installed globally

But if you have not installed typescript try this command: npm install typescript

Answer 6

I had the same problem. If you have installed first nodejs by apt and then you use the tar.gz from nodejs.org, you have to delete the folder located in /usr/lib/node_modules.