Internal working of reduce function in javascrip does not return any value please debug

function reduce(array, callback, initialValue) {
   for(let i=0;i<array.lenght;i++)
        initialValue = callback(initialValue,array[i]);
  return initialValue;

const nums = [4, 1, 3];
const add = function(a, b) { return a + b; }
reduce(nums, add, 0);//-> 8

I’ve edited your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (’).

You have a typo in your loop conditions.