CODEWITHSUNDEEP
javascripttypescriptweb-worker
overexchange
overexchange

Reputation: 1

error TS2554: Expected 2-3 arguments, but got 1

With given tsconfig.json,

{

    "compilerOptions": {

      "lib": ["es2015", "dom"]
    },
    "files": [
      "./project1/tstut.ts",
      "./project1/worker.ts"

    ]
  }

and folder structure

1)

For below code(./project1/tstut.ts),

if(window.Worker){
  console.log('Workers are available');
}
....
let worker: Worker = new Worker('worker.js');
worker.postMessage('do some work')

How to resolve below typescript error?

Property 'Worker' does not exist on type 'Window'

2)

For below worker code(./project1/worker.ts), 

self.addEventListener('message', (e) => {
    // console.log(e)
    if(e.data === 'do some work'){
        console.log('Worker is about to start some work');
        let count: number =0;
        for(let i: number=0; i<1000; i++){
            count += i;
        }
        self.postMessage({message:count});
    }

})

JS allows syntax self.postMessage({message: count})

https://github.com/Microsoft/TypeScript/issues/582

Given scenario does not fit in my case.

How to resolve below error for postMessage()? On running tsc

Expecting 2-3 arguments, but got 1

Upvotes: 3

Views: 16821

Answers (1)

Bodman
Bodman

Reputation: 8046

Workers don't live on the window object. 

if (typeof(Worker) !== "undefined") {
    // Yes! Web worker support!
    // Some code.....
} else {
    // Sorry! No Web Worker support..
}

To get around your webworker postMessage error, either use 'webworker' lib in tsconfig or the following

const ctx: Worker = self as any;
...
ctx.postMessage({message:count});

Your code example

tstut.js

if(typeof(Worker) !== 'undefined'){
    const worker = new Worker('worker.js');
    worker.postMessage('do some work');
    worker.addEventListener('message', function (e) {
        //console.log(e);
        console.log(e.data);
    });
}

worker.js (No need to check for worker support here)

const ctx: Worker = self as any;
ctx.addEventListener('message', (e) => {
    // console.log(e)
    if (e.data === 'do some work') {
        console.log('Worker is about to start some work');
        let count: number = 0;
        for (let i: number = 0; i < 1000; i++) {
            count += i;
        }
        ctx.postMessage({ message: count });
    }
})

Upvotes: 14

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