Does JavaScript have a method like “range()” to generate a range within the supplied bounds?

Question

In PHP, you can do...

range(1, 3); // Array(1, 2, 3)
range(\"A\", \"C\"); // Array(\"A\", \"B\", \"C\")

That is, there is a function that l

Answer 1

range(start,end,step): With ES6 Iterators

You only ask for an upper and lower bounds. Here we create one with a step too.

You can easily create range() generator function which can function as an iterator. This means you don't have to pre-generate the entire array.

function * range ( start, end, step = 1 ) {
  let state = start;
  while ( state < end ) {
    yield state;
    state += step;
  }
  return;
};

Now you may want to create something that pre-generates the array from the iterator and returns a list. This is useful for functions that accept an array. For this we can use Array.from()

const generate_array = (start,end,step) =>
  Array.from( range(start,end,step) );

Now you can generate a static array easily,

const array1 = generate_array(1,10,2);
const array1 = generate_array(1,7);

But when something desires an iterator (or gives you the option to use an iterator) you can easily create one too.

for ( const i of range(1, Number.MAX_SAFE_INTEGER, 7) ) {
  console.log(i)
}

Special Notes

• If you use Ramda, they have their own R.range as does Lodash