[javascript bug] app.setInterval crashes with function parameter SOLVED

[Mathew]

When using the new app.setInterval with a function parameter that encloses app.clearInterval, the application will crash after the interval is cleared.

To reproduce, run in the console:

Code: Select all

{
let intervalTimer = new Date();
// test built-in interval function
let interval = app.setInterval( function testInterval() {

    let stopTimer = (new Date() - intervalTimer) > 5 * 1000;
    if (stopTimer) {
        app.clearInterval(interval);
        if ( 4 === app.alert({cMsg:"Do you need more time?", nIcon: 2, nType: 2}))  {

            intervalTimer = new Date();
            // restart
            interval = app.setInterval( testInterval, 500);
        }
    }
    console.println('click...' + Math.ceil(10 - (new Date() - intervalTimer)/500));
}, 500);

}

The application (builds 393 and 394) crashes every time I press "Cancel".

Workaround
My current workaround is a recursive setTimeOut.

[Daniel - PDF-XChange]

Hello, Mathew

Thank you for the report, I have reproduced this in build 395 as well, and passed it along to the Dev team for review.

Kind regards,

[Roman - Tracker Supp]

Hi Mathew,
The bug has been fixed for the upcoming v10.6 release of the Editor.

[Roman - Tracker Supp]

Mathew, you might find it suitable to use this utility class:

Code: Select all

class AsyncIntervalGenerator {
    constructor(t) {
        this.count = 0;
        this.interval = app.setInterval(
            () => this.resolve({value : this.count++, done : false}), 
            t
        );
    }
    next() {
        return new Promise((resolve) => this.resolve = resolve);
    }
    return() {
        app.clearInterval(this.interval);
        return Promise.resolve({value : undefined, done : true});
    }

    [Symbol.asyncIterator]() {
        return this;
    }    
}

It will allow to simplify your interval related code. For example:

Code: Select all

async function doIntervalWork() {
    for await (const i of new AsyncIntervalGenerator(500)) {
        if ((i + 1) % 10 == 0) {
            if ( 4 !== app.alert({cMsg:"Do you need more time?", nIcon: 2, nType: 2})) 
                break;
        }
        console.println(`${i + 1} bits of work`);                 
    }
    return 'Done';
}

doIntervalWork().then((status) => console.println(`Finished with status '${status}'`));
console.println('Started');

Or, if you want to completely separate the interval management logic from the actual payload, you can split the doIntervalWork function like this:

Code: Select all

async function* workIntervals() {
    for await (const i of new AsyncIntervalGenerator(500)) {
        if ((i + 1) % 10 == 0) {
            if ( 4 !== app.alert({cMsg:"Do you need more time?", nIcon: 2, nType: 2})) 
                break;
        }
	yield i;              
    }  
}

async function doIntervalWork() {
    for await (const i of workIntervals()) {
        console.println(`${i + 1} bits of work`);                 
    }
}

[Mathew]

Thanks for that Roman! I'm just starting to get my head around async functions. This is really helpful.

[Roman - Tracker Supp]

You are welcome!

[Roman - Tracker Supp]

By the way, the Editor supports a few extensions to Adobe JS API that facilitate Javascript async features.
For example, global.changed:

Code: Select all

async function monitorGlobal(varName) {
  try {
      for(;;) {
          const newValue = await global.changed(varName);
          console.println(`New value for ${varName}: ${newValue}`);
      }
  } catch {
      console.println(`${varName} deleted`);
  }
}

if (app.doc) { // global.changed follows global.subscribe security restrictions and works only with document-originated globals
	monitorGlobal('v1').then(()=>console.println('Monitoring completed'));
	app.setTimeOut('global.v1=1;', 1);
	app.setTimeOut('global.v1=2;', 1000);
	app.setTimeOut('delete global.v1;', 2000);
}

Another is app.timeOut.