@extra-array/intersection/index.js

Gives values present in both arrays.

'use strict';
function id(v) {
    return v;
}
function cmp(a, b) {
    return a < b ? -1 : (a > b ? 1 : 0);
}
function from$$1(x) {
    return Array.isArray(x) ? x : [...x];
}
function from(vs, fm = null) {
    return new Set(fm ? from$$1(vs).map(fm) : vs);
}
function intersectionMap(x, y, fm = null) {
    var s = from(y, fm);
    var fm = fm || id;
    var a = [], i = -1;
    for (var u of x) {
        var u1 = fm(u, ++i, x);
        if (s.has(u1))
            a.push(u);
    }
    return a;
}
function intersectionDual(x, y, fc = null, fm = null) {
    var fc = fc || cmp, fm = fm || id;
    var y1 = [...y].map(fm);
    var a = [], i = -1;
    x: for (var u of x) {
        var u1 = fm(u, ++i, x);
        for (var v1 of y1)
            if (fc(u1, v1) === 0) {
                a.push(u);
                continue x;
            }
    }
    return a;
}
function intersection(x, y, fc = null, fm = null) {
    if (fc)
        return intersectionDual(x, y, fc, fm);
    else
        return intersectionMap(x, y, fm);
}
module.exports = intersection;