Cesium.js vs index.cjs vs index.js?

All 3 of these files are similar in contents and size, but not exact:


What are the differences? and are all of them needed?


Cesium.js is IIFE, meaning it’s a script that can be loaded in the browser to define a global Cesium variable will all members of the library.

index.cjs is CommonJS, mostly used in NodeJS.

index.js is an ESM module, which is used in both NodeJS and in the browser.

I would recommend using index.js if you’re unsure of which is appropriate for your app.