jsweird/lib/weird.js

Translate from normal javascript to weird javascript

// Yaroslav Gaponov (yaroslav.gaponov@gmail.com)

function buildNumber(i) {
    switch (i) {
        case 0:
            return '+[]';
        case 1:
            return '+!![]';
        default:
            return buildNumber(i >> 1) + buildNumber(i - (i >> 1));
    }
}

function _buildSymbol(code, c) {
    const s = eval(code);
    const indx = s.indexOf(c);
    if (indx !== -1) {
        return '((' + code + ')[' + buildNumber(indx) + '])';
    }
    return;
}

function buildSymbol(c) {
    return _buildSymbol('!![]+[]', c) ||
        _buildSymbol('![]+[]', c) ||
        _buildSymbol('[][' + buildNumber(0) + ']+[]', c) ||
        _buildSymbol('[]+{}', c) ||
        _buildSymbol('(+[])[' + string('constructor') + ']+[]', c) ||
        _buildSymbol('([]+[])[' + string('constructor') + ']+[]', c) ||
        _buildSymbol('([]+[])[' + string('constructor') + ']+[]', c) ||
        _buildSymbol('+[][' + string('constructor') + ']((' + buildNumber(1) + ')+(' + buildSymbol('e') + ')+(' + buildNumber(5) + ')+(' + buildNumber(0) + ')+(' + buildNumber(0) + '))+[]', c) ||
        (c >= '0' && c <= '9' && _buildSymbol('(' + buildNumber(c.charCodeAt(0) - '0'.charCodeAt(0)) + ')[' + string('toString') + '](' + buildNumber(36) + ')', c)) ||
        (c >= 'a' && c <= 'z' && _buildSymbol('(' + buildNumber(10 + c.charCodeAt(0) - 'a'.charCodeAt(0)) + ')[' + string('toString') + '](' + buildNumber(36) + ')', c)) ||
        _buildSymbol(`[][${string('filter')}][${string('constructor')}](${string('return escape')})()([]+{})`, c) ||
        `([][${string('filter')}][${string('constructor')}](${string('return unescape')})()(${string('%')} + ${string(('0' + c.charCodeAt(0).toString(16).toLowerCase()).substr(-2))}))`
}

function string(s) {
    const code = [];
    for (let i = 0; i < s.length; i++) {
        code.push(buildSymbol(s[i]));
    }
    return code.join('+');
}

function main(s) {
    return `[][${string('filter')}][${string('constructor')}](${string(s)})()`;
}

module.exports = s => main(s);