How do you split an array into array pairs in JavaScript?

Question

I want to split an array into pairs of arrays.

var arr = [2, 3, 4, 5, 6, 4, 3, 5, 5]

would be

var newarr = [
    [2, 3],
           


        

Answer 1

Here is another generic solution that uses a generator function.

/**
 * Returns a `Generator` of all unique pairs of elements from the given `iterable`.
 * @param iterable The collection of which to find all unique element pairs.
 */
function* pairs(iterable) {
    const seenItems = new Set();
    for (const currentItem of iterable) {
        if (!seenItems.has(currentItem)) {
            for (const seenItem of seenItems) {
                yield [seenItem, currentItem];
            }
            seenItems.add(currentItem);
        }
    }
}

const numbers = [1, 2, 3, 2];
const pairsOfNumbers = pairs(numbers);

console.log(Array.from(pairsOfNumbers));
// [[1,2],[1,3],[2,3]]

What I like about this approach is that it will not consume the next item from the input until it actually needs it. This is especially handy if you feed it a generator as input, since it will respect its lazy execution.