What does Three points in Javascript? known as the Spread or Rest Operator


The three points may refer to:

Usage example

Object Merge

You use it for object merge

obj1 = { color: "blue" };
obj2 = { color: "red", length: 10 };
obj3 = { name: "TheName" };
console.log('With Spread');
console.log({...obj1, ...obj2, ...obj3});
  • Result: Note that the values in conflict are overwritten and not added. The last object to the right has precedence.



The spread syntax 1) allows an expression to be expanded in places where multiple arguments (for function calls) or multiple elements (for array literals) or multiple variables (for destructuring assignment) are expected.

Spread syntax can be applied only to iterable objects

  • For function calls:
  • For array literals:
[...iterableObj, 4, 5, 6];


The rest parameter 2) syntax allows to represent an indefinite number of arguments as an array.

  • For function definition:
function f(a, b, ...theArgs) {
  // ...


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