[SOLVED] How create custom iterator that skips empty value in Javascript

How create custom iterator that skips empty value in Javascript

Cusomt iterator in Javascript

Hi, I would like to create a Javascript class that overrides Symbol.iterator in order to skip the data that are null or undefined.

Example

  const simple = new SimpleClass([
    {
      fields: `a`,
    },
    {
      fields: `b`,
    },
    {
      fields: undefined,
    },
    {
      fields: null,
    },
    {
      fields: `e`,
    },
  ]);

  for (const val of simple) {
    console.log(val); // a b e
  }

Here is where I've started: Defining an iterable with a class

Can you help me to draft a solution for my use-case?

Thanks!

Solution

class SimpleClass {
  #items
  constructor(items) {
    this.#items = items
  }

  *[Symbol.iterator]() {
    for (const item of this.#items) {
      if (item.fields !== null && item.fields !== undefined) {
        yield item.fields
      }
    }
  }
}

const simple = new SimpleClass([{
    fields: `a`,
  },
  {
    fields: `b`,
  },
  {
    fields: undefined,
  },
  {
    fields: null,
  },
  {
    fields: `e`,
  },
]);

for (const val of simple) {
  console.log(val); // a b e
}