freeCodeCamp/guide/english/certifications/javascript-algorithms-and-data-structures/basic-data-structures/copy-an-array-with-the-spread-operator/index.md

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Copy an Array with the Spread Operator

Copy an Array with the Spread Operator

• The final hint in the example tells you to use a recently learned method.
• The spread operator copies all elements into a new empty object.

while (num >= 1) {
    newArr = [...arr]
    num--;
}

• The code above will copy all of the elements into newArr but will also reinitialise newArr with every new iteration of the while loop.
• A new variable should first be initialised using the spread operator - let obj = [...arr]; - then this variable should be added to the newArr for every iteration of the while loop.

Solution:

function copyMachine(arr, num) {
  let newArr = [];
  while (num >= 1) {
    // change code below this line
    newArr.push([...arr]);
    // change code above this line
    num--;
  }
  return newArr;
}

// change code here to test different cases:
console.log(copyMachine([true, false, true], 2));