如何修复对象“属性未定义”键v / discordjs

如何解决如何修复对象“属性未定义”键v / discordjs

我目前正在为我的机器人开店，并且正在执行购买命令。我决定将用户的库存作为对象存储在数据库中，但是，当我第一次尝试从商店购买商品（在这种情况下，是风扇）时，它会成为（空白）对象，但随后返回：

UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'fan' of undefined

以下是代码：https://github.com/boomermath/grapeoverhaul/blob/master/commands/t.js

module.exports = {
    name: 't',description: 'dig to earn stars',cooldown: 0,execute(message,args,d) {
//blank object to initialize in the db
const blankObj = {}
//items in the shop and their cost
const itemCost = {
    fan: 100,orangedetector: 100,mangodetector: 50,carrotdetector: 50,starmagnet: 100,starmill: 400
}
async function buy() {
     //get person's inventory
    let have = await d.items.get(message.author.id);
    //if they arent in the db,initialize
    if (have === undefined || have === null) {
    await d.items.set(message.author.id,blankObj)
    }
    //argument parsing,get item and number of items user wants
    let regex = /\d+/g;
    let numberOfItemsRaw = args.join(' ').match(regex);
    let numberOfItems = parseInt(numberOfItemsRaw);
    let item = args.join(' ').replace(numberOfItems,'').replace(' ','');
     //if they don't specify a number assume one.
      if (numberOfItemsRaw === NaN || numberOfItemsRaw === null || numberOfItemsRaw === undefined) {
        numberOfItems = 1;
    }
    //because some idot is gonna put 0,i guarantee it
    if (numberOfItems === 0) {
        message.channel.send('ok karen');
        return;
    }
    //if item is not in the shop,then big oof
if (!Object.keys(itemCost).includes(item)) {
        message.channel.send("dude that's not an item in the shop");
        return;
    }
    //total cost
    let total = itemCost[item] * numberOfItems;
    //if ur broke
    if (total > await d.users.get(message.author.id)) {
        message.channel.send('you donut have enough money,rip');
        return;
    }
    //take money
    d.addMoni(message.author.id,-total)
    //intialize item property to store item
    if (have[item] === undefined || have[item] === null) {
    have[item] = 0;
    }
   //give item(s)
    have[item] += numberOfItems
   //put in db
    d.items.set(message.author.id,have);
    message.channel.send(item);
    message.channel.send(numberOfItems);
}
buy();
    }
};

我该如何解决它而不返回未定义的错误？

解决方法

当have为空或未定义时，您忘记初始化await d.items.get(message.author.id)。

//get person's inventory
let have = await d.items.get(message.author.id);
//if they arent in the db,initialize
if (have === undefined || have === null) {
    await d.items.set(message.author.id,blankObj);
    have = blankObj; // <<
}

因此，当您尝试评估have时，undefined不会是have[item]。