yargify.js

/**
 * Convert cli-style arguments to reasonable key-value hashmap object
 * @param {string[]} args Raw cli args
 * @param {boolean} dropFirstTwo Useful for nodejs (drops two leading args)
 * @returns Object<string|number|boolean>
 * @example
 *     yargify(['--foo=bar', '--qux="hello world", '--fred', '-x=42', '-y=false'])
 *         // => {foo: 'bar', qux: 'hello world', fred: true, x: 42, y: false}
 */
function yargify(args, dropFirstTwo=true) {
    const valueDelimiter = '=';
    const shortKeyRe = /^-([^-])$/;
    const longKeyRe = /^--([^-]{2,})$/;
    const quotedRe = /^"[\s\S]*"$/;
    const numberRe = /^(\n+)|(\n*\.\n+)$/;
    const booleanRe = /^true|false$/i;

    if (dropFirstTwo) {
        args = args.slice(2);
    }

    return args.reduce((result, item) => {
        const parts = item.split(valueDelimiter);
        let key;
        let value;
        switch (parts.length) {
            case 1:
                key = parts[0];
                value = true;
                break;
            case 2:
                key = parts[0];
                value = parts[1];
                break;
            default:
                key = parts.shift();
                value = parts.join(valueDelimiter);
                break;
        }

        if (shortKeyRe.test(key)) {
            key = key.replace(shortKeyRe, '$1');
        } else if (longKeyRe.test(key)) {
            key = key.replace(longKeyRe, '$1');
        }

        if ((typeof value === 'string') && (quotedRe.test(value) || numberRe.test(value) || booleanRe.test(value))) {
            value = JSON.parse(value);
        }

        result[key] = value;
        return result;
    }, {});
}