@extra-array/group/index.js

Breaks array keeping similar values together.

'use strict';
function id(v) {
    return v;
}
function cmp(a, b) {
    return a < b ? -1 : (a > b ? 1 : 0);
}
function group(x, fc = null, fm = null) {
    var fc = fc || cmp, fm = fm || id;
    var a = [], b = [];
    var u1, i = -1;
    for (var v of x) {
        var v1 = fm(v, ++i, x);
        if (i === 0 || fc(u1, v1) === 0)
            b.push(v);
        else {
            a.push(b);
            b = [v];
        }
        u1 = v1;
    }
    a.push(b);
    return a;
}
module.exports = group;