时间戳

首页 > 解决方案 > javascript：在 JSON 响应中找不到数据

javascript - javascript：在 JSON 响应中找不到数据

问题描述

我想使用 twitter 和 spotify API 在 twitter 上创建一个机器人。到目前为止，我已经有了一个好的开始，但是现在我遇到了一个我自己无法解决的问题：

我需要知道艺术家的名字和 Spotify 前 50 首歌曲中前 1 名的歌曲。所以我发送了一个 Spotify API 请求，我得到了这个 json 响应：

{
  "href" : "https://api.spotify.com/v1/playlists/37i9dQZEVXbIPWwFssbupI/tracks?offset=0&limit=1",
  "items" : [ {
    "added_at" : "1970-01-01T00:00:00Z",
    "added_by" : {
      "external_urls" : {
        "spotify" : "https://open.spotify.com/user/"
      },
      "href" : "https://api.spotify.com/v1/users/",
      "id" : "",
      "type" : "user",
      "uri" : "spotify:user:"
    },
    "is_local" : false,
    "primary_color" : null,
    "track" : {
      "album" : {
        "album_type" : "single",
        "artists" : [ {
          "external_urls" : {
            "spotify" : "https://open.spotify.com/artist/7IlRNXHjoOCgEAWN5qYksg"
          },
          "href" : "https://api.spotify.com/v1/artists/7IlRNXHjoOCgEAWN5qYksg",
          "id" : "7IlRNXHjoOCgEAWN5qYksg",
          "name" : "Aya Nakamura",
          "type" : "artist",
          "uri" : "spotify:artist:7IlRNXHjoOCgEAWN5qYksg"
        } ],
        "available_markets" : [ "AD", "AE", "AL", "AR", "AT", "AU", "BA", "BE", "BG", "BH", "BO", "BR", "BY", "CA", "CH", "CL", "CO", "CR", "CY", "CZ", "DE", 
"DK", "DO", "DZ", "EC", "EE", "EG", "ES", "FI", "FR", "GB", "GR", "GT", "HK", "HN", "HR", "HU", "ID", "IE", "IL", "IN", "IS", "IT", "JO", "JP", "KW", "KZ", "LB", "LI", "LT", "LU", "LV", "MA", "MC", "MD", "ME", "MK", "MT", "MX", "MY", "NI", "NL", "NO", "NZ", "OM", "PA", "PE", "PH", "PL", "PS", "PT", "PY", "QA", "RO", "RS", "RU", "SA", "SE", "SG", "SI", "SK", "SV", "TH", "TN", "TR", "TW", "UA", "US", "UY", "VN", "XK", "ZA" ],
        "external_urls" : {
          "spotify" : "https://open.spotify.com/album/43sqDUJkvHHK0ikoAN4JAS"
        },
        "href" : "https://api.spotify.com/v1/albums/43sqDUJkvHHK0ikoAN4JAS",
        "id" : "43sqDUJkvHHK0ikoAN4JAS",
        "images" : [ {
          "height" : 640,
          "url" : "https://i.scdn.co/image/ab67616d0000b273e2e7c5322770c06bdfead61f",
          "width" : 640
        }, {
          "height" : 300,
          "url" : "https://i.scdn.co/image/ab67616d00001e02e2e7c5322770c06bdfead61f",
          "width" : 300
        }, {
          "height" : 64,
          "url" : "https://i.scdn.co/image/ab67616d00004851e2e7c5322770c06bdfead61f",
          "width" : 64
        } ],
        "name" : "Jolie nana",
        "release_date" : "2020-07-17",
        "release_date_precision" : "day",
        "total_tracks" : 1,
        "type" : "album",
        "uri" : "spotify:album:43sqDUJkvHHK0ikoAN4JAS"
      },
      "artists" : [ {
        "external_urls" : {
          "spotify" : "https://open.spotify.com/artist/7IlRNXHjoOCgEAWN5qYksg"
        },
        "href" : "https://api.spotify.com/v1/artists/7IlRNXHjoOCgEAWN5qYksg",
        "id" : "7IlRNXHjoOCgEAWN5qYksg",
        "name" : "Aya Nakamura",
        "type" : "artist",
        "uri" : "spotify:artist:7IlRNXHjoOCgEAWN5qYksg"
      } ],
      "available_markets" : [ "AD", "AE", "AL", "AR", "AT", "AU", "BA", "BE", "BG", "BH", "BO", "BR", "BY", "CA", "CH", "CL", "CO", "CR", "CY", "CZ", "DE", "DK", "DO", "DZ", "EC", "EE", "EG", "ES", "FI", "FR", "GB", "GR", "GT", "HK", "HN", "HR", "HU", "ID", "IE", "IL", "IN", "IS", "IT", "JO", "JP", "KW", "KZ", "LB", "LI", "LT", "LU", "LV", "MA", "MC", "MD", "ME", "MK", "MT", "MX", "MY", "NI", "NL", "NO", "NZ", "OM", "PA", "PE", "PH", "PL", "PS", "PT", "PY", "QA", "RO", 
"RS", "RU", "SA", "SE", "SG", "SI", "SK", "SV", "TH", "TN", "TR", "TW", "UA", "US", "UY", "VN", "XK", "ZA" ],
      "disc_number" : 1,
      "duration_ms" : 147076,
      "episode" : false,
      "explicit" : false,
      "external_ids" : {
        "isrc" : "FRZ042000666"
      },
      "external_urls" : {
        "spotify" : "https://open.spotify.com/track/34FbkFgAbv4ffvhL2XQMVm"
      },
      "href" : "https://api.spotify.com/v1/tracks/34FbkFgAbv4ffvhL2XQMVm",
      "id" : "34FbkFgAbv4ffvhL2XQMVm",
      "is_local" : false,
      "name" : "Jolie nana",
      "popularity" : 83,
      "preview_url" : "https://p.scdn.co/mp3-preview/f38309ea40d6b20b4a7a6b72209b503342b1b147?cid=8f22024a4f144cd7b965b9db6e124e94",
      "track" : true,
      "track_number" : 1,
      "type" : "track",
      "uri" : "spotify:track:34FbkFgAbv4ffvhL2XQMVm"
    },
    "video_thumbnail" : {
      "url" : null
    }
  } ],
  "limit" : 1,
  "next" : "https://api.spotify.com/v1/playlists/37i9dQZEVXbIPWwFssbupI/tracks?offset=1&limit=1",
  "offset" : 0,
  "previous" : null,
  "total" : 50
}

我将该响应放入变量myJSON中，并且我想创建一个仅包含的变量Aya Nakamura和另一个仅包含的变量Jolie Nana

我已经尝试使用检索数据myJSON.items，myJSON[items]但是这两行都返回undefined

我希望我已经解释得很好。

感谢您的帮助，请原谅我的英语，因为我会说法语。

标签： javascriptnode.jsarraysjsonarraylist

解决方案

您没有解析 json，因此您的数据类型不是您怀疑的对象，而是字符串。此外，您可以像解析字符串一样访问字符串的属性，但它们返回未定义的，而不是您想要的数据。这里有一些例子：

const data = `
{"foo": "bar"}
`
console.log('data:', typeof data, data)

const parsedData = JSON.parse(data)

// Notice how similar this looks to the other in the console. 
// It is not always clear what the type is if you don't check it,
// since JSON strings look similar to JS objects
console.log('parsedData:', typeof parsedData, parsedData) 

// accessing an item:

console.log('data.foo:', data.foo) // since this is a string, it is `undefined`
console.log('parsedData.foo:', parsedData.foo) // since this is a parsed object, it works

推荐阅读