JSZip produces TS2322 error in node.js using typescript - node.js

Question

After adding the import statement:
import JSZip from 'jszip';
The build will produce an error:
TS2322: Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.
For these lines of code:
const env: string = process.env.NODE_ENV;
...
private timeoutTime: number = process.env.VUE_APP_TIME_OUT;
...
node.js version: 14.16.1
jszip version: 3.7.1
typescript: 3.9.4
Removing the import for JSZip the error goes away.
There are multiple instances of this same error - but not in every case where process.env is used.
Not sure how to resolve this.

Answer 1

the properties in process.env have a type string | undefined you have two options
first
cast them props to yow desired type
const env = process.env.NODE_ENV as string;
second
create a file call types.d.ts at yow package.json add a prop call types and set the path to yow new file types.d.ts
{
....
"types":"./types.d.ts",
....
}
in yow tsconfig.json there is a prop call typeRoots assuming yow "baseUrl": "./node_modules"
yow typesRoots will look like:
//tsconfig.json
{
"baseUrl": "./node_modules",
"typeRoots": [
"../types.d.ts",
]
}
add this to the new file
/// <reference types="node" />
declare namespace NodeJS {
interface ProcessEnv {
readonly NODE_ENV: "development" | "production" | "test";
readonly PUBLIC_URL: string;
readonly PORT: string;
}
}
Now add all yow vars there all them vars you set there will have a type string