Object.Prototype方法和IIFE中的“使用严格”（立即调用的函数表达式）

The original Code:

原始代码:

'use strict';
function GitJs(config) {
    var defaults = {
        inheriting: false,
        clientId: undefined,
        accessToken: undefined,
        baseUrl: 'https://api.github.com',
        mode: 'read'
    };

    this.config = $.extend(defaults, config);
}

/**
 * Gets the jQuery method that GitJs#generateApiRequest is going to use to send the ajax request.
 *
 * @param {string} httpVerb The HTTP verb that the request will use,
 * @return string
 */
GitJs.prototype.getCommandMethod = function (httpVerb) {
    var method = $.get;

    switch (httpVerb) {
    case 'GET':
        method = $.get;
        break;
    case 'POST':
        method = $.post;
        break;
    }
    return method;
};

...
'use strict';
func