How to enable JavaScript IntelliSense for custom file extensions in VS Code?

Question

The question title says it all. My organization uses a non-standard file extension on source code written using JavaScript. Changing the file extension to ".js" seems to activate IntelliSense.

However, I was wondering if the IntelliSense could be activated using the non-standard file extension.

Answer 1

Click the bottom right of the window where it says "Plain Text" or the name of the detected language. This will bring up a menu at the top that lets you change it for the current session and also configure that specific extension to always be interpreted as JS.

Answer 2

Use the files.associations setting:

"files.associations": {
  "*.customExtension": "javascript"
}