@extra-array/zip/index.js

Combines values from arrays.

'use strict';
function id(v) {
    return v;
}
function someBool(x) {
    for (var i = 0, I = x.length; i < I; i++)
        if (x[i])
            return true;
    return false;
}
function some(x, ft = null) {
    if (ft)
        return x.some(ft);
    else
        return someBool(x);
}
function zip(xs, fm = null, ft = null, vd) {
    var fm = fm || id, ft = ft || some;
    var X = xs.length, a = [];
    if (X === 0)
        return a;
    var ds = new Array(X).fill(false);
    var ls = xs.map(x => x.length);
    for (var i = 0;; i++) {
        for (var j = 0, vs = []; j < X; j++) {
            ds[j] = i >= ls[j];
            vs[j] = ds[j] ? vd : xs[j][i];
        }
        if (ft(ds))
            break;
        a.push(fm(vs, i, null));
    }
    return a;
}
module.exports = zip;