Variables, values, references, copying

Primitive values vs objects

Primitive values behave as values:

• string
• number
• boolean
• bigint
• symbol
• undefined
• null

Objects include:

• object
• array
• function
• Map
• Set
• Date
• class instances

Variables hold references to objects.

const a = {
  value: 10,
};
const b = a;
b.value = 20;

console.log(a.value); // 20