NodeJS為什么不在我的IF/Else陳述句中呼叫我的函式

我有一個關于節點和在 if/else 陳述句中呼叫函式的問題。下面是我的情況。我不確定為什么從第一個 IF 陳述句呼叫 awsCreds 函式會起作用，但是當我嘗試從 else 陳述句呼叫它時它不起作用。它是否與我在 else 陳述句中有一個 if/else 的事實有關？

let cacheExpiration;
let currentTime;
let awsCredentials;

async function stsGetCallerIdentity(creds, message) {
   const stsParams = { credentials: creds };
   // Create STS service object
   const kinesis = new AWS.Kinesis(stsParams);
   const parsed_value = JSON.parse(message);
   const type = parsed_value.type;
   console.info(type);

   const message_type = {
      "transcript": process.env.TRANSCRIPT_KINESIS,
      "tone": process.env.TONE_KINESIS,
      "pitch": process.env.PITCH_KINESIS
   };
   const stream_name = message_type[type];
   console.info(stream_name);

   const params = {
      Data: Buffer.from(message),
      PartitionKey: `1111`,
      StreamName: stream_name
   };
   kinesis.putRecord(params, function(err, data) {
      if (err) console.error(err);
      else {
         console.info(JSON.stringify(data));
      }
   });
}

function awsCreds() {
   return new Promise((resolve, reject) => {
      const roleToAssume = {
         RoleArn: process.env.IAMRole,
         RoleSessionName: `session1`,
         DurationSeconds: 900 };

      sts.assumeRole(roleToAssume, function(err, data) {
         if (err) {
            console.error(err, err.stack);
            reject(err.stack);
         } else {
            awsCreds = {
               accessKeyId: data.Credentials.AccessKeyId,
               secretAccessKey: data.Credentials.SecretAccessKey,
               sessionToken: data.Credentials.SessionToken,
               cacheExpiration: data.Credentials.Expiration
            };
            resolve(awsCreds);
         }
      });
   });
};

webSocketClient.on(`message`, async (message) => {
try {
  currentTime = new Date();
  console.log(`currentTime`, currentTime);
  console.log(`cacheExpiration`, cacheExpiration);


          if (cacheExpiration == undefined) {
            //Calling awsCreds returns values.
           awsCredentials = await awsCreds();
           stsGetCallerIdentity(awsCredentials, message)
    
        } else {
           const minutes = (cacheExpiration.getTime() - currentTime.getTime());
           console.log(`minutes`, minutes);
           if (minutes > 60000) {
              //Do something
           stsGetCallerIdentity(awsCredentials, message)
           } else {
              
              // Calling awsCreds from here returns error 'awsCreds is      not a function'.
console.log(`Refreshing credentials`);
              awsCredentials = await awsCreds();
              stsGetCallerIdentity(awsCredentials, message)
           }
        }
       
     } catch (error) {
        console.error(`There was an error`, error);
     };
)};

uj5u.com熱心網友回復：

你的函式被呼叫awsCreds，然后你awsCreds在你之前分配為一個物件文字resolve，你需要const在前面，或者根本不分配只是把物件放在決議中：

改變

awsCreds = {
   accessKeyId: data.Credentials.AccessKeyId,
   secretAccessKey: data.Credentials.SecretAccessKey,
   sessionToken: data.Credentials.SessionToken,
   cacheExpiration: data.Credentials.Expiration
};
resolve(awsCreds);

到

resolve({
   accessKeyId: data.Credentials.AccessKeyId,
   secretAccessKey: data.Credentials.SecretAccessKey,
   sessionToken: data.Credentials.SessionToken,
   cacheExpiration: data.Credentials.Expiration
});

標籤：节点.js

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