All Objects Are Related

All built-in types — Array, Date, Function, String — use prototypal inheritance. This is where all their methods come from.

The Full Prototype Chain

[1, 2, 3]  →  Array.prototype  →  Object.prototype  →  null
              (.map, .push...)    (.toString...)

• .push(), .map(), .filter() — live on Array.prototype.
• .toString(), .valueOf() — live on Object.prototype, accessible to all.

Primitives and Wrappers

When you call "hello".toUpperCase(), JS temporarily wraps the string in new String("hello") to access String.prototype methods, then discards the wrapper.