@extra-array/selection-sort/index.js

Arranges values in an order.

'use strict';

/**
 * Compares two values.
 * @param a a value
 * @param b another value
 * @returns a<b: -1, a=b: 0, a>b: 1
 */
function cmp(a, b) {
    return a < b ? -1 : (a > b ? 1 : 0);
}

function selectionSortPair$(x, fc, m) {
    var X = x.length, diff = x !== m;
    for (var i = 0; i < X - 1; i++) {
        var l = i;
        for (var j = i + 1; j < X; j++)
            if (fc(m[l], m[j]) > 0)
                l = j;
        {
            var t = x[i];
            x[i] = x[l];
            x[l] = t;
        }
        if (diff) {
            var u = m[i];
            m[i] = m[l];
            m[l] = u;
        }
    }
    return x;
}
/**
 * Arranges values in an order.
 * @param x an array (updated)
 * @param fc compare function (a, b)
 * @param fm map function (v, i, x)
 * @returns x
 */
function selectionSort$(x, fc = null, fm = null) {
    var fc = fc || cmp;
    if (fm)
        return selectionSortPair$(x, fc, x.map(fm));
    else
        return selectionSortPair$(x, fc, x);
}

/**
 * Arranges values in an order.
 * @param x an array
 * @param fc compare function (a, b)
 * @param fm map function (v, i, x)
 */
function selectionSort(x, fc = null, fm = null) {
    return selectionSort$(x.slice(), fc, fm);
}

module.exports = selectionSort;