mbell8903/passport-auth-token

'use strict';

/**
 * Looks up a value on the object.
 * @param {Object} obj The object to look through.
 * @param {String} field The name of the field to check.
 * @param {Object} [options] The lookup options.
 * @param {Boolean} options.caseInsensitive Whether or not to do case insensitive checking.
 * @returns {String} The property name.
 */
exports.lookup = function (obj, field, options) {
    if (!obj) {
        return null;
    }

    options = options || {};

    const chain = field.split(']').join('').split('[');

    for (let i = 0, len = chain.length; i < len; i++) {
        const prop = options.caseInsensitive ? obj[chain[i].toLowerCase()] : obj[chain[i]];

        if (typeof prop === 'undefined') {
            return null;
        }

        if (typeof prop !== 'object') {
            return prop;
        }

        obj = prop;
    }

    return null;
};