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 below:

Cannot find module 'typescript'
Error: Cannot find module 'typescript'
    at Function.Module._resolveFilename (module.js:469:15)
    at Function.Module._load (module.js:417:25)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (C:\Users\mypc\Documents\Angular Projects\my-angular-app\node_modules\@angular\cli\models\config\config.js:5:12)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)

Do you have any idea how to fix this? Thanks.

install it globally and set path in environmental variables. — Aravind, Jun 18 '17 at 03:36
I have installed it globally just now. Do you have a more specific guide to set path in environmental variables? — redshot, Jun 18 '17 at 03:39
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/146980/discussion-between-aravind-and-redshot). — Aravind, Jun 18 '17 at 04:00

score 146 · Answer 1 · edited Feb 16 '21 at 02:19

146

For me just running the below command is not enough (though a valid first step):

npm install -g typescript

The following command is what you need (I think deleting node_modules works too, but the below command is quicker)

npm link typescript

edited Feb 16 '21 at 02:19

GabLeRoux

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answered Feb 03 '19 at 17:28

DanAbdn

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npm link typescript also worked for my nodejs project. thanks – ChinaHelloWorld Feb 19 '19 at 07:07
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If I could give you 14 upvotes I would. This did it for me. Everything broke after a node.js update. – wildbagel Dec 26 '19 at 14:33
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anyone know why this doesnt happen during the install? – techsaint Jan 16 '20 at 05:38
I installed that with "npm install -g typescript" and then used this command to update typescript "npm install -g npm". But, my problem has not been solved until now. – Arash Yazdani Aug 27 '20 at 09:11
I already had TypeScript installed so I just did `npm link typescript` and it worked for me. – Aosu Terver Jan 25 '21 at 09:18

score 83 · Answer 2 · edited Feb 16 '21 at 02:18

83

This should do the trick,

npm install -g typescript

edited Feb 16 '21 at 02:18

GabLeRoux

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answered Jun 18 '17 at 03:36

Sajeetharan

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Hi @Sajeetharan I have installed it globall using your command above. After running "ng serve" again , I am still prompted with: Cannot find module 'typescript' Error: Cannot find module 'typescript' – redshot Jun 18 '17 at 03:41
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try to uninstall angular-cli globally, run npm cache clean and reinstall. – Sajeetharan Jun 18 '17 at 03:42
i have installed angular globally with "npm install -g @angular/cli" – redshot Jun 18 '17 at 03:43
uninstall it and do the fresh installation as above – Sajeetharan Jun 18 '17 at 03:44
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This answer is doing the trick for me every time I don't have typescript installed globally. – skiabox Oct 16 '17 at 20:51
Only installing TypeScript locally with --save fixed the issue for me Found it here: https://www.bountysource.com/issues/32351321-uncaught-error-cannot-find-module-typescript – Satish P Feb 04 '19 at 03:22
But this is not really the solution. you should *link* the **global package** to the **local one** in `node_module` by runnig: `npm link typescript` – MoHo Oct 26 '19 at 10:28

redshot · Accepted Answer · 2021-02-04T14:33:01.687

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

edited Feb 04 '21 at 14:33

answered Jun 22 '17 at 04:35

redshot

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Nice one. This worked for me when I had already tried the above solution. I was patching a local project with some project files from a tutorial that is slightly old. It kinda broke things, but deleting node_modules and running npm install fixed everything. – Tezza Nov 23 '18 at 13:18
Maybe instead to use `npm install` you can use `npm ci` – NsdHSO Jul 07 '22 at 21:40

score 11 · Answer 4 · edited Jun 24 '23 at 07:24

11

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

Global installation

yarn global add typescript

Local installation

yarn add --dev typescript

edited Jun 24 '23 at 07:24

Gedeon Mutshipayi

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answered Oct 29 '19 at 09:39

freedev

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Torsten Barthel · Answer 5 · 2018-04-10T03:24:49.643

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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.

edited Apr 10 '18 at 03:24

answered Apr 10 '18 at 03:18

Torsten Barthel

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score 3 · Answer 6 · answered Oct 30 '20 at 10:56

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Run: npm link typescript if you installed globally

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

answered Oct 30 '20 at 10:56

NsdHSO

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score 2 · Answer 7 · answered Sep 04 '19 at 17:17

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If you use yarn instead of npm, you can install typescript package for that workspace by running:

yarn add typescript

or you can install it globally by running:

sudo yarn global add typescript

to be available for any project.

answered Sep 04 '19 at 17:17

Abdollah

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score 1 · Answer 8 · answered Nov 09 '17 at 15:17

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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.

answered Nov 09 '17 at 15:17

Agustin Larreinegabe

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score 1 · Answer 9 · answered Apr 11 '18 at 03:31

I had a very similar problem after moving a working project to a new subdirectory on my file system. It turned out I had failed to move the file named .angular-cli.json to the subfolder along with everything else. After noticing that and moving the file into the subdirectory, all was back to normal.

score 1 · Answer 10 · answered Jun 11 '19 at 09:08

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Run 'npm install' it will install all necessary pkg .

answered Jun 11 '19 at 09:08

SATISH RAJNALE

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fixed it for me – Daniel Methner Jul 15 '20 at 07:07

score 1 · Answer 11 · edited Aug 03 '20 at 12:19

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If you have cloned your project from git or somewhere then first, you should type npm install.

edited Aug 03 '20 at 12:19

Divya Pusuluru

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answered Jul 20 '20 at 15:15

Qodir Amirov

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This is a duplicate of one of the nine existing answers on this three year old question. When adding an answer to an older question with an accepted answer it is very important to point out what new aspect of the question your answer addresses. – Jason Aller Jul 20 '20 at 15:37

score 0 · Answer 12 · answered Jun 23 '21 at 13:09

0

The best way is to do: npm install or npm i

this way all dependencies will be added.

answered Jun 23 '21 at 13:09

Sarthak Maheshwari

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Sandro Antônio Souza · Answer 13 · 2022-05-15T20:33:13.390

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I had this same problem using npm run start-dev as configured my package.json ("start-dev": "nodemon src/index.ts"). When i used nodemon src/index.ts in cmd work just fine, but to use npm run start-dev i had to use npm link typescript, it solve the problem.

edited May 15 '22 at 20:33

answered May 15 '22 at 20:32

Sandro Antônio Souza

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

13 Answers13

NPM Installation Method

Yarn Installation Method

Linked