Async gives syntax error in a method(function)

Asked Sep 29 '18 at 15:01

Active Sep 29 '18 at 15:08

Viewed 127 times

Environment: Node.js v7.2.0

I am trying to use async keyword to create method that returns a promise.

I get the following error:

SyntaxError: Unexpected token function

this.getFrame = async function(data) {
                      ^^^^^^^^

Here is the example:

function Parser() {
  this.receiveBuffer = Buffer.alloc(0);
  this.frameBuff = Buffer.alloc(0);

  /* GET FRAME ******************************** */
  this.getFrame = async function(data) { //The ERROR appears here!!!
    for (let byte of data) {
      if (byte !== 0x0d && byte !== 0x0a) {
        // console.log()
        this.receiveBuffer = Buffer.concat([
          this.receiveBuffer,
          Buffer.from([byte])
        ]);
        // console.log("Buffer is long: " + this.receiveBuffer.length);
      } else {
        this.frameBuff = this.receiveBuffer;
        this.receiveBuffer = Buffer.alloc(0);
        // console.log(this.frameBuff);
        return this.frameBuff;
      }
    }
  };
  /* ******************************** */

  this.parse = function(frame) {
    console.log(frame);
  };
}

edited Sep 29 '18 at 15:08

mplungjan

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asked Sep 29 '18 at 15:01

Hairi

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browser IE11 by any chance? – Jaromanda X Sep 29 '18 at 15:03
Where are you trying to run this code? Looks like your environment doesn't support async/await syntax. – Bergi Sep 29 '18 at 15:04
Node.js version 7.2.0 – Hairi Sep 29 '18 at 15:04
1

Btw, nothing that you do inside this function appears to be asynchronous, so why are you trying to use a promise at all? – Bergi Sep 29 '18 at 15:05
ahhh, yeah, you need later node – Jaromanda X Sep 29 '18 at 15:05
Please always start your quest by googling the error message - Even for X/Y problems ;) – mplungjan Sep 29 '18 at 15:06
@Bergi It returns only when valid frame is received, hence after undefined time – Hairi Sep 29 '18 at 15:06
that's not what async/await is for ... oh and `It returns only when valid frame is received` no, it doesn't – Jaromanda X Sep 29 '18 at 15:07
Why not.......? – Hairi Sep 29 '18 at 15:09
Yes the Node is too old. – Hairi Sep 29 '18 at 15:09
because there's nothing asynchronous at all in that function - that's why not – Jaromanda X Sep 29 '18 at 15:09
How do you define asynchronous? – Hairi Sep 29 '18 at 15:10
@Hairi The function returns as soon as the loop is finished. It doesn't wait for any outside event. – Bergi Sep 29 '18 at 15:10
think setTimeout – Jaromanda X Sep 29 '18 at 15:11
If you can do `let parsedData = Parser.getFrame(someData); console.log(parsedData)` and not see undefined, then it is not async – mplungjan Sep 29 '18 at 15:11
Ok all, I installed Node.js `v10.11.0` and it works now. The SO question marked as a duplicate is correct. Thank you all. – Hairi Sep 29 '18 at 15:29

Async gives syntax error in a method(function)

0 Answers0