尽管有超级调用,但未定义超级类属性

Super Class Property Undefined Despite Super Call

本文关键字:未定义 属性 调用      更新时间:2023-09-26

我正试图使用ECMAScript 6编写一个文本冒险游戏,并使用Babel将其转换为ECMAScript5。我遇到了一个奇怪的案例,它没有出现在我的代码中。

我有一个通用的操作类,它解析命令,确定给定的输入是否与触发该操作的命令匹配,然后调用函数来实际执行该操作。

/**
 * An action represents a mapping between a string and some kind of action in
 * the system.
 */
export class Action {
    /**
     * Construct a new action instance.
     */
    constuctor () {
        this.commands = [];
    }
    /**
     * Add a command as a trigger for this action.
     *
     * @param {String} command The command string to add as a trigger.
     *
     * @returns {Boolean} True if the command was added, false otherwise.
     */
    addCommand (command) {
        var paramRegex = /'{([a-zA-Z0-9_]+)'}/g;
        var i = 0;
        var regexResult;
        var commandRegex;
        var parameters;
        if (typeof command !== 'string' || command.length < 1) {
            return false;
        }
        parameters = {};
        // Make spaces generic
        commandRegex = command.replace(/'w+/g, '''w+');
        regexResult = paramRegex.exec(commandRegex);
        while (regexResult) {
            parameters[i] = regexResult[1];
            commandRegex = commandRegex.replace(regexResult[0], '([^''w]+)');
            i++;
            regexResult = paramRegex.exec(commandRegex);
        }
        this.commands.push({
            regex: new RegExp(commandRegex, 'gi'),
            parameters: parameters
        });
        return true;
    }
    /**
     * Determine if the action has a trigger matching the given command string.
     *
     * @param {String} command The command to parse.
     *
     * @returns {Boolean} True if the command triggers the action, false
     * otherwise.
     */
    isTrigger (command) {
        var i;
        for (i = 0; i < this.commands.length; i++) {
            if (this.commands[i].regex.test(command)) {
                return true;
            }
        }
        return false;
    }
    /**
     * Trigger the action using the given command. This method checks if the
     * command is a trigger for the action, extracts any arguments from the
     * command string, and passes them to the {@link Action#execute} function
     * using {@link Function#apply}.
     *
     * @param {String} command The command to use to trigger the action.
     *
     * @returns {Boolean} True if the trigger was successful, false otherwise.
     */
    trigger (command) {
        var args;
        var result;
        var i;
        for (i = 0; i < this.commands.length; i++) {
            result = this.commands[i].regex.exec(command);
            if (result != null) {
                break;
            }
        }
        if (result == null) {
            return false;
        }
        args = [];
        for (i = 1; i < result.length; i++) {
            args.push(result[i]);
        }
        this.execute.apply(this, args);
    }
    /**
     * Execute the action with the given arguments.
     *
     * @returns {Boolean} True if the execution was successful, false otherwise.
     *
     * @virtual
     */
    execute () {
        throw new Error('Not implemented');
    }
}

我有一个子类,它应该实现一个移动动作,并将玩家从一个位置移动到另一个位置。

/**
 * An action that moves the player.
 *
 * @extends {Action}
 */
export class MoveAction extends Action {
    constructor () {
        super();
        this.addCommand('go to {place}');
        this.addCommand('move to {place}');
        this.addCommand('go {place}');
    }
    execute (place) {
        var loc = GameObject.getGameObject(place);
        if (!loc) {
            return false;
        }
        return player.setLocation(loc);
    }
}

我已经在我的代码上运行了Babel,以生成兼容的ECMAScript 5代码,并试图通过Node.JS手动运行它们,以在将它们推送到我的Git存储库之前验证它们的工作情况(我计划稍后编写测试用例)。

不过,我遇到了一个问题,Node.JS抱怨this.commands未定义。

> var MoveAction = require('./compiled/actions/moveAction').MoveAction;
undefined
> var act = new MoveAction();
TypeError: Cannot read property 'push' of undefined
    at MoveAction.addCommand (compiled'action.js:64:26)
    at new MoveAction (compiled'actions'moveAction.js:41:39)
    at repl:1:11
    at REPLServer.defaultEval (repl.js:248:27)
    at bound (domain.js:280:14)
    at REPLServer.runBound [as eval] (domain.js:293:12)
    at REPLServer.<anonymous> (repl.js:412:12)
    at emitOne (events.js:82:20)
    at REPLServer.emit (events.js:169:7)
    at REPLServer.Interface._onLine (readline.js:210:10)

我无法立即发现我所写的内容有任何错误,我在当前代码的其他地方也做了类似的事情,没有任何问题。我会继续研究,看看我是否能自己解决这个问题,但如果有人能为我节省时间,我将不胜感激。

解决了这个问题,我把constructor拼错成了constuctor