How To Solve “Cannot find name ‘process'” Error in TypeScript

The error “Cannot find name ‘process'” Error in TypeScript occurs because we have not installed types for node. To fix this error, we can run the command suggested in the error message and change some configurations in the file tsconfig.json

The cause of the “Cannot find name ‘process'” error in TypeScript

This error occurs because we have not installed the data type for NodeJS. Let’s look at an example of the error when using ExpressJs with TypeScript.

Error Example:

const port = process.env.PORT || 3000;

Error Output:

Cannot find name 'process'. Do you need to install type definitions for node? Try npm i --save-dev @types/node

In the above example, we set up a process to register port 3000 to the ExpressJs server, but TypeScript could not recognize the process object and gave an error message. In the error message, NodeJS has suggested us a command to fix the error. In many cases, just running the install can fix the error.

Solution for the “Cannot find name ‘process'” Error in TypeScript

To be able to fix this error, we will proceed to install types for NodeJS, and at the same time, we should also change some settings in the tsconfig.json file

Install the node types

First, we will follow the NodeJS instructions by running the syntax in the error message, this is the fastest fix, and in many cases, the error will be fixed after running this syntax.

npm i --save-dev @types/node

If running the above syntax to install types for node still fails, we will add some settings to the tsconfig.json file.

Add “node” into “types” array

We will open the tsconfig.json file, then navigate to the types array area and add “node”, once added to the tsconfig.json file we have to restart the IDE for the changes to take effect.

{
  "compilerOptions": {
    "types": ["node"]
  }
}

But if you have done the above steps and still can’t fix the error, we only have this last way

Delete node_modules folder

We will proceed to delete the entire node_modules folder and also the package-lock.json file to reinstall it like new. This is a rare occurrence, but with this method, you will undoubtedly resolve the problem. After deleting, you proceed to reinstall the modules by running the following syntax

npm install

The above syntax will reinstall the modules you used before. Then you restart the IDE for the changes to take effect.

Summary

In summary, we already know why the “Cannot find name ‘process'” error in TypeScript occurs. We also fixed it by installing the types for the node and changing some configurations in the tsconfig.json, in many cases, just running the command that NodeJS suggests to fix the error.

Carolyn Hise

Carolyn Hise has three years of software development expertise. Strong familiarity with the following languages is required: Python, Typescript/Nodejs, .Net, Java, C++, and a strong foundation in Object-oriented programming (OOP).