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Start your free trialTurandeep Munday
6,047 PointsWhy can i not increment values in an array using for of even when using let
let array = [1,2,3];
console.log(array);
for ( let arr of array ) {
arr ++;
console.log(arr)
console.log(array)
};
Is this because arr will loop through the values but these are in local scope and don't affect the array lietral?
2 Answers
Steven Parker
231,210 PointsYou're right, the loop variable "arr" is local in scope and only contains a copy of the current array element's value. So incrementing it will not affect the original array.
Modifying the array is easily done in a conventional loop:
for (let i = 0; i < array.length; i++) {
array[i]++;
}
Or using the "map" method:
array = array.map(arr => ++arr); // note: post-increment won't work here
Turandeep Munday
6,047 PointsThanks - I assume it's not possible to change the array values in a let.. of
loop?
Steven Parker
231,210 PointsNot by modifying the loop variable. That's why a different kind of loop would make more sense.
Turandeep Munday
6,047 PointsTurandeep Munday
6,047 PointsI was expecting the array to be returned with all values in the array added by +1 but this wasn't the case.