Javascript - "this" is empty

我正在尝试使用 Node.js 为我的 Web 应用程序编写服务器端。提取以下代码以模拟情况。问题是应用程序在尝试访问 actionExecute "方法" 中的 this.actions.length 时崩溃。属性 this.actions 在那里是未定义的（这个 == {} 在范围内），即使它是在"构造函数"（请求函数本身）中定义的。如何使动作属性也可以从其他"方法"访问？

var occ = {
    exampleAction: function(args, cl, cb)
    {
        // ...
        cb('exampleAction', ['some', 'results']);
    },
    respond: function()
    {
        console.log('Successfully handled actions.');
    }
};
Request = function(cl, acts)
{
    this.client = cl;
    this.actions = [];
    this.responses = [];
    // distribute actions
    for (var i in acts)
    {
        if (acts[i][1].error == undefined)
        {
            this.actions.push(acts[i]);
            occ[acts[i][0]](acts[i][1], this.client, this.actionExecuted);
        }
        else
            // such an action already containing error is already handled,
            // so let's pass it directly to the responses
            this.responses.push(acts[i]);
    }
}
Request.prototype.checkExecutionStatus = function()
{
    // if all actions are handled, send data to the client
    if (this.actions == [])
        occ.respond(client, data, stat, this);
};
Request.prototype.actionExecuted = function(action, results)
{
    // remove action from this.actions
    for (var i = 0; i < this.actions.length; ++i)
        if (this.actions[i][0] == action)
            this.actions.splice(i, 1);
    // and move it to responses
    this.responses.push([action, results]);
    this.checkExecutionStatus();
};
occ.Request = Request;
new occ.Request({}, [['exampleAction', []]]);