How to create windowed slice of array in JavaScript?

Question

I\'m looking for an array method implementation named Array.window(n) that invoked on an array with parameter n, would give a contiguous overlappin

Answer 1

Here is a simple rolling window function. Notice that we can determine the number of iterations based on array length minus the desired window size.

/**
 * Produces a rolling window of desired length {w} on a 1d array.
 * 
 * @param {Array} a The 1d array to window.
 * @param {Number} w The desired window size.
 * @return {Array} A multi-dimensional array of windowed values.
 */
function rolling(a, w) {
    let n = a.length;
    let result = [];

    if (n < w || w <= 0) {
        return result;
    }

    for (let i = 0; i < n - w + 1; i++) {
        result.push(a.slice(i, w + i));
    }

    return result;
}

let a = [1, 2, 3, 4, 5];
console.log(JSON.stringify(rolling(a, 3)));