@extra-array/unique/index.js

Removes duplicate values.

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