Visual Studio Code - TypeScript type checking - recognize external objects in JavaScript project

Question

Have enabled TypeScript checking in a JavaScript-only project in VS Code using the global setting

"javascript.implicitProjectConfig.checkJs": true

The type checking works, but for every external/global variable it shows a 'cannot find name' error:

$('body').addClass('something'); // cannot find name '$'

MyCustomObject.doSomething(); // cannot find name 'MyCustomObject'

How can I make VS Code recognize these global variables ? I think that this needs to be done using a custom definition file specified in a jsconfig.json, but haven't been able to make it work.

UPDATE:

Not a duplicate of Enabling implicit type checking for Javascript in VS Code results in "Cannot find name 'require'" error .

Have seen that ticket and it is related only to a node.js project and the accepted answer is related to installing the type definition npm package for nodejs. Which is not the case here. I need to set up a custom defintion file

Answer 1

You can declare global types as shown in https://www.typescriptlang.org/docs/handbook/declaration-files/templates/global-modifying-module-d-ts.html

Keep the declared types as any so that tsc doesn't complain about not being a function or not having properties.

Create an index.d.ts file in the root folder with content

declare global {
    var $: any;
    var MyCustomObject: any;
}
export {};

After changing the index.d.ts file restart VSCode to make it recognize the types.