@extra-array/range/index.js

Finds smallest and largest entries.

'use strict';
function id(v) {
    return v;
}
function cmp(a, b) {
    return a < b ? -1 : (a > b ? 1 : 0);
}
function range(x, fc = null, fm = null) {
    var fc = fc || cmp, fm = fm || id;
    var mi = -1, mu, mv;
    var ni = -1, nu, nv;
    var i = -1;
    for (var u of x) {
        var v = fm(u, ++i, x);
        if (i === 0 || fc(v, mv) < 0) {
            mi = i;
            mu = u;
            mv = v;
        }
        if (i === 0 || fc(v, nv) > 0) {
            ni = i;
            nu = u;
            nv = v;
        }
    }
    return [[mi, mu], [ni, nu]];
}
module.exports = range;