Javascript forEach循环-如何重建它？

Question

In Ruby, we can reconstruct the each loop for an array using the 1) while loop, 2) yield statement (to pass value to a block), and 3) class Array (to make the method available to the Array class); as follows:

class Array
    def reconstructed_each
        n = 0
        while n < self.length
            yield(self[n])
            n += 1
        end
        self
    end
end

In Javascript, I reconstructed the forEach loop for an array using a similar fashion; as follows:

Array.prototype.reconstructedforEach = function(c) {
    var n = 0;
    while (n < this.length) {
        c(this[n]);
        n += 1;
    }
};

The part I am not sure about is how to make the above function available to arrays only, but not other types of object eg number.

UPDATE: I have it figured out. The above code snippet has been edited accordingly.

Answer 1

Are you just looking for a way to iterate a javascript array using the while-construct?

if so:

const arr = ["some", "value", "here"];
let i =0;

while(i < arr.length){
 //use contents of arr[i] to do something useful
 i++;
}

Perhaps I'm missing something

Answer 2

Maybe you're looking for something like generator functions?

const myArray = [1,2,3,4,5];
function* constructEach(){
  let index = 0;
  while(index < 3)
    yield myArray[index++];
}

var gen = constructEach();

console.log(gen.next().value); // 0
console.log(gen.next().value); // 1
console.log(gen.next().value); // 2
console.log(gen.next().value); // undefined

(This example was shamelessly stolen from MDN )