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How to known Tesseract has terminated the job in order to start next function? It's running as an async function but i need to start next function when OCR is done. I tried to start when OCR string is not empty but my next function starts before. Should i use "Promise" option ? If yes, how? Here, Tesseract basic example used:

const { createWorker } = require('tesseract.js');
const worker = createWorker();
(async () => {
 await worker.load();
 await worker.loadLanguage('eng');
 await worker.initialize('eng');
 const { data: { text } } = await 
 worker.recognize('myimage.png');
 console.log(text);
 await worker.terminate();
})();
                Doens't your example already tell you how to do it? Instead of console.log place the "next function" at this position that you want to call.
– some-user
                Sep 11, 2022 at 8:31
                yes it is. But if i place this Tessaract async function into a loop in order to read several pictures, Tesseract reads the next picture before execute "console.log(text);".
– Teddol
                Sep 11, 2022 at 13:10
                You have to await that function. I'd suggest to dive it bit into Promises and async/await :-)
– some-user
                Sep 11, 2022 at 13:15
                Thanks, but i'm new in javascript and it's difficult for me to explore Promise process... could you share a simple example to understand how it works ?
– Teddol
                Sep 11, 2022 at 13:24
A (potentially over-)simplified explanation: An async function is a function that will do some work in an asynchronous manner. It will return before this work is actually completed (and the next instruction will be evaluated). Therefore it cannot return the result of this work, but will return the promise of the result.
If you want to wait till the asynchronous work is done, you'll have to await the promise. Only then the actual result will be available. Simple example:
async function doSomething() {
  // This line takes take 2s to continue
  await new Promise((r) => setTimeout(r, 2000))
  console.log('3')
  return 42
async function main() {
  console.log('1')
  const promise = doSomething()
  console.log('2')
  console.log('promise:', promise)
  const result = await promise
  console.log('4')
  console.log('result:', result)
main()
So, if you want to wait for the result of worker.recognize you use await like in the code you posted. If you want to wrap all that in a function, that function will be async and you have to await it if you want to run them sequentially:
const { createWorker } = require('tesseract.js');
const worker = createWorker();
async function runOcr(filename) {
  const { data: { text } } = await worker.recognize(filename);
  // Now do something with the result:
  console.log(text);
async function main() {
  // Setup
  await worker.load();
  await worker.loadLanguage('eng');
  await worker.initialize('eng');
  // Process different files
  await runOcr('myimage.png')
  await runOcr('myimage2.png')
  // Tear down
  await worker.terminate();
main()
                Sorry, that was a copy and paste mistake - or a check if you really try to understand it ;-)
– some-user
                Sep 11, 2022 at 20:06
        
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