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Spread Operator in JavaScript

April 5, 2026

Spread Operator (...)

Expand arrays/objects/iterables inline.

Spread Examples

// Array spread
let arr1 = [1, 2, 3];
let arr2 = [...arr1, 4, 5]; // [1, 2, 3, 4, 5]

// Function arguments
Math.max(...arr1); // 3

// Object spread
let obj1 = {a: 1, b: 2};
let obj2 = {...obj1, c: 3}; // {a:1, b:2, c:3}

// Clone arrays/objects
let cloned = [...originalArray];
let clonedObj = {...originalObj};

Key Points

  • Shallow copy for arrays/objects.
  • Array concatenation without concat().
  • Function call with dynamic arguments.
  • Merges objects (later overrides earlier).
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