我正在尝试使用我在 this.then() function 中获得的返回值。我不知道如何修复它

Question

我正在尝试使用我在 discord 机器人 function 中的 this.then() function 中获得的返回值来发送他们输入的任何股票价格的消息。 当我在 discord function 中运行 function 时，它显示“未定义”但正确的价格被记录在.then() function 中。请帮助！

const alpha = require("alphavantage")({ key: "KEY" });

const { Client, Intents } = require("discord.js");
const Discord = require("discord.js");

const client = new Client({
  intents: [Intents.FLAGS.GUILDS, Intents.FLAGS.GUILD_MESSAGES],
});

const tickers = ["CVE", "SU", "AAPL", "TSLA", "CNQ", "FUBO", "FB"];
const prefix = ".";

client.once("ready", () => {
  console.log("Bot is Ready!");
});

getInput();

function getInput() {
  client.on("message", (msg) => {
    if (!msg.content.startsWith(prefix) || msg.author.bot) return;

  const args = msg.content.slice(prefix.length).trim().split(" ");
  const command = args.shift().toLowerCase();

  if (command === "list") {
    msg.channel.send(tickers.join(", "));
  } else if (command == "add") {
    tickers.push(args[0]);
  } else if (command == "price") {
    console.log(getStockPrices(args[0]));
  }
  });
client.login("KEY");
}

function getStockPrices(stock) {
 let prices = [];

 alpha
   .experimental("TIME_SERIES_INTRADAY", {
    symbol: stock,
    market: "USD",
    interval: "5min",
  })
  .then((data) => {
    for (let key in data["Time Series (5min)"]) {
    let openPrice = data["Time Series (5min)"][key]["1. open"];
    prices.push(openPrice);
   }
  console.log(prices[0]);
  return prices[0];
 });
}

Answer 1

您必须等待您的 promise，或定义一个then回调：

async function getInput() {//async
  client.on("message", (msg) => {
    if (!msg.content.startsWith(prefix) || msg.author.bot) return;

  const args = msg.content.slice(prefix.length).trim().split(" ");
  const command = args.shift().toLowerCase();

  if (command === "list") {
    msg.channel.send(tickers.join(", "));
  } else if (command == "add") {
    tickers.push(args[0]);
  } else if (command == "price") {
    console.log(await getStockPrices(args[0]));//await
  }
  });
client.login("KEY");
}

或者

function getInput() {
  client.on("message", (msg) => {
    if (!msg.content.startsWith(prefix) || msg.author.bot) return;

  const args = msg.content.slice(prefix.length).trim().split(" ");
  const command = args.shift().toLowerCase();

  if (command === "list") {
    msg.channel.send(tickers.join(", "));
  } else if (command == "add") {
    tickers.push(args[0]);
  } else if (command == "price") {
    getStockPrices(args[0]).then(console.log); //then
  }
  });
client.login("KEY");
}

有了承诺，结果是异步的。 实际上，您必须在另一个 function 中返回您的 promise：

function getStockPrices(stock) {
 let prices = [];

 return alpha //there, return your promise
   .experimental("TIME_SERIES_INTRADAY", {
    symbol: stock,
    market: "USD",
    interval: "5min",
  })
  .then((data) => {
    for (let key in data["Time Series (5min)"]) {
    let openPrice = data["Time Series (5min)"][key]["1. open"];
    prices.push(openPrice);
   }
  console.log(prices[0]);
  return prices[0];
 });
}

你应该阅读 Javascript Promises，它会帮助你理解你在做什么。