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Mitchell
Mitchell

Posted on • Edited on

Iterable - JavaScript Challenges

You can find all the code in this post in the repo Github.


Iterable related challenges


Iterable

Rewriting the Symbol.iterator properity to create an iterator object.

The iterator object includes two properties:

  1. value: the current value of the current iteration call, undefined when the iterator is over.
  2. done: whether the iteration has finished.
/**
 * @param {any} data
 * @return {object}
 */

function createCustomIterable(data) {
  return {
    [Symbol.iterator]() {
      let index = 0;
      return {
        next() {
          if (index < data.length) {
            return {
              value: data[index++],
              done: false,
            };
          } else {
            return {
              value: undefined,
              done: true,
            };
          }
        },
      };
    },
  };
}

// Usage example:
const customIterable = createCustomIterable([1, 2, 3, 4]);

// Using for...of loop
for (const item of customIterable) {
  console.log(item);
}
/**
 * 1
 * 2
 * 3
 * 4
 */

// Using spread operator
const arrayFromIterable = [...customIterable];
console.log(arrayFromIterable); // => [1, 2, 3, 4]

// Using Array.from()
const anotherArray = Array.from(customIterable);
console.log(anotherArray); // => [1, 2, 3, 4]
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