As with almost every programming language, JavaScript treats various types of values differently. A string like “Hello world” is very different from a number like 42.

Data types in JavaScript variables Variables hold a wide variety of information temporarily. The JavaScript data types that can be stored in a variable include: ...

Microsoft is opening up Excel to developers with a new JavaScript API. It will let developers use custom data types like images, cards, and arrays.

Standards proposal would allow annotations to be checked by external type checkers like TypeScript but treated as comments by the JavaScript engine.