javascript - 检查邀请时如下

Question

如果我在打开机器人时创建一个新的服务器快速邀请，则会发生错误。在其他情况下，它有效

const invites = {};
const wait = require('util').promisify(setTimeout);
client.on('ready', () => {
  wait(1000);
    g.fetchInvites().then(guildInvites => {
      invites[g.id] = guildInvites;
    });
  });
});
client.on('guildMemberAdd', member => {
   member.guild.fetchInvites().then(guildInvites => {
     const ei = invites[member.guild.id];
     invites[member.guild.id] = guildInvites;
     const invite = guildInvites.find(i => ei.get(i.code).uses < i.uses);
     const inviter = client.users.get(invite.inviter.id);
     const logChannel = member.guild.channels.find(channel => channel.name === "join-logs");
     logChannel.send(`${member.user.tag} joined using invite code ${invite.code} from ${inviter.tag}. Invite was used ${invite.uses} times since its creation.`);
   });
 });

错误:

2019-07-07T09:49:20.363359+00:00 app[worker.1]: Unhandled Rejection: 
2019-07-07T09:49:20.363377+00:00 app[worker.1]:  TypeError: Cannot read property 'uses' of undefined
2019-07-07T09:49:20.363378+00:00 app[worker.1]:     at guildInvites.find.i (./bot.js:398:57)
2019-07-07T09:49:20.363380+00:00 app[worker.1]:     at Map.find (./node_modules/discord.js/src/util/Collection.js:160:13)
2019-07-07T09:49:20.363381+00:00 app[worker.1]:     at member.guild.fetchInvites.then.guildInvites (./bot.js:398:33)
2019-07-07T09:49:20.363382+00:00 app[worker.1]:     at process._tickCallback (internal/process/next_tick.js:68:7)

398截止日期

const invite = guildInvites.find(i => ei.get(i.code).uses < i.uses);

Answer 1

使用的邀请是新的，尚未在缓存中。但是，ei.get(i.code).uses 假设它是，并在它不存在时尝试使用它的属性。

此修改后的谓词函数将返回未缓存的邀请，或使用增加的邀请。

const invite = guildInvites.find(i => !ei.get(i.code) || ei.get(i.code).uses < i.uses);