index.js

"use strict";

function persianAlphabeticCompare(s1, s2) {
    var persian_alphabet_fix_map = {
        'ؤ': 1608.5,
        'ئ': 1610,
        'پ': 1577,
        'ة': 1607.5,
        'ۀ': 1607.5,
        'ژ': 1586.5,
        'ک': 1603,
        'چ': 1580.5,
        'گ': 1603.5,
        'ی': 1609,
        'ي': 1609,
        '۰': 1632,
        '۱': 1633,
        '۲': 1634,
        '۳': 1635,
        '۴': 1636,
        '۵': 1637,
        '۶': 1638,
        '۷': 1639,
        '۸': 1640,
        '۹': 1641
    }

    // For simplicity, just ignore the range that includes Arabic diacritics.
    var ignore_range = [1611, 1631];

    for (var i = 0, j = 0; ; i++, j++) {
        var c1, c2;

        for (; i < s1.length; i++) {
            c1 = s1.charCodeAt(i);
            if (c1 < ignore_range[0] || c1 > ignore_range[1])
                break;
        }
        for (; j < s2.length; j++) {
            c2 = s2.charCodeAt(j);
            if (c2 < ignore_range[0] || c2 > ignore_range[1])
                break;
        }

        if (i === s1.length && j === s2.length) return 0;
        if (i === s1.length) return -1;
        if (j === s2.length) return 1;

        var cmp_value =
            (persian_alphabet_fix_map[s1[i]] || c1) -
            (persian_alphabet_fix_map[s2[j]] || c2);
 
        if (cmp_value) return cmp_value;
    }
}

module.exports = persianAlphabeticCompare;