Return 来自模块未定义

Question

嗨，我制作了一个模块，当我尝试 return 歌曲名称时，它只是未定义，console.log 就在它工作之前，所以我有点困惑。 console.log(`"${songName}" by ${artistsList}`) 之后的那一行是问题所在，我尝试 return "${songName}" by ${artistsList} 但 return 是只是未定义所以我有点不明白为什么

代码：（这是spotify.js模块）我用 const Spotify = require("./spotify.js") 调用它，一切正常，直到我只需要 return 使用 Spotify.request() 函数

的歌曲名称]

const axios = require("axios");

module.exports = {
    token: "",
    ref: "",
    refresh: function () {
      axios({
        method: "post", //you can set what request you want to be
        url: "https://accounts.spotify.com/api/token",
        data:
          `grant_type=refresh_token&refresh_token=${this.ref}`,
        headers: {
          Authorization:
            "Basic ",
          "Content-Type": "application/x-www-form-urlencoded"
        }
      }).then(response => {
        this.token = response.data.access_token
        console.log(`Successfully refreshed token ${module.exports.token}`);
      });
    },
    analyseSong: function (data) {
      console.log(data)
      const x = data;
      //console.log(x)
      if (x.is_playing) {
        const songNameMatch = x.item.name.split("(");
        var songName = x.item.name;
        try {
          const letter = songNameMatch[1].charAt(0);
          letter.toLowerCase() == "f" ||
            songNameMatch[1].toLowerCase().match(/^with/)
            ? (songName = songNameMatch[0].trim())
            : false;
        } catch (err) {
          false;
        }
        var artistArray = [];
        var artist;
        const artists = x.item.artists;
        //console.log(token)
        for (artist in artists) {
          artistArray.push(x.item.artists[artist].name);
        }
  
        //console.log(artistArray)
  
        const artistsList = artistArray.join(", ");
        //console.log(artistsList)
        //console.log(`Currently playing: ${songName} - ${artistsList}`);
        console.log(`"${songName}" by ${artistsList}`)
        return `"${songName}" by ${artistsList}`;
      } else {
        return `Not currently listening to a song`;
      }
    },
    request: function () {
      axios
        .get("https://api.spotify.com/v1/me/player/currently-playing", {
          headers: { Authorization: `Bearer ${this.token}` }
        })
        .then(function (response) {
          module.exports.analyseSong(response.data);
        })
    },
  }

Answer 1

So I'm doing X=Spotify.request() trying to get the song name as X so I can output using IRC chat

有几个问题。 .request() 根本没有 return 值。因此，它永远不会 return 除了 undefined 以外的任何东西。您可以通过添加两个 return 语句来解决这个问题，第一个 return 承诺本身，第二个使 analyseSong() 中的 return 值成为解析值承诺：

request: function () {
  return axios
    .get("https://api.spotify.com/v1/me/player/currently-playing", {
      headers: { Authorization: `Bearer ${this.token}` }
    })
    .then(function (response) {
      return module.exports.analyseSong(response.data);
    })
},

现在 Spotify.request() 将 return 一个承诺，该承诺将使用 return 来自 .analyseSong(response.data) 的值解析。您可以像这样使用该承诺：

Spotify.request().then(result => {
   console.log(result);
}).catch(err => {
   console.log(err);
});

Return 来自模块未定义

Return from module is undefined

module

node.js