I want to create a loop that will continue until it reaches an error then continues on...

for (var m = 0; m != 'Error'; m++)

If I push the iterations too high, it will throw a "TypeError", which indicates that the limit has been reached. This for loop exists inside another loop which needs to continue and not crash the script, just discontinue the loop.

Thanks!

EDIT CODE FOLLOWS:

for (var i = 0; i < 100; i++) {
  var xml = fs.readFileSync('./Filename-' + (i + 100) + '.xml', 'utf-8');
  var level1 = bb(xml)
  for (var m = 0;; m++) {
    try {
     if (level1.data.level2[m].product.code == '7472558') {
        console.log(level1.data.level2[m].product.code);
        total++}
    }
    catch (e) {
     break;
    }
  }
console.log(total)
}

I want to create a loop that will continue until it reaches an error then continues on...

for (var m = 0; m != 'Error'; m++)

If I push the iterations too high, it will throw a "TypeError", which indicates that the limit has been reached. This for loop exists inside another loop which needs to continue and not crash the script, just discontinue the loop.

Thanks!

EDIT CODE FOLLOWS:

for (var i = 0; i < 100; i++) {
  var xml = fs.readFileSync('./Filename-' + (i + 100) + '.xml', 'utf-8');
  var level1 = bb(xml)
  for (var m = 0;; m++) {
    try {
     if (level1.data.level2[m].product.code == '7472558') {
        console.log(level1.data.level2[m].product.code);
        total++}
    }
    catch (e) {
     break;
    }
  }
console.log(total)
}

• javascript
• loops
• for-loop

• 1 m will never equal an error, just some integer. Do you set m anywhere in the body of the for loop? – Matthew Herbst Commented Apr 10, 2016 at 1:17
• Use try..catch to handle a thrown error. Insert it between the two loops. – Jonathan Lonowski Commented Apr 10, 2016 at 1:19
• Yes, "m" represents a numbered iteration, I do not know the upper bounds, and there should not be a numbered upper-bound, as "m" could represent hundreds – 2xshot Commented Apr 10, 2016 at 1:24
• Why use the error to terminate the inner loop instead of looping while m < level1.data.level2.length? – andyk Commented Apr 10, 2016 at 2:12
• @andyk Ahhh... you're right that's a better fix. totally forgot about the .length, it was staring right at me the whole time! Thanks! – 2xshot Commented Apr 10, 2016 at 2:23

2 Answers 2

You can wrap the code that throws the error in a try and then break in the catch block:

for (var m = 0;; m++) {
  try {
    // code that throws the error
  } catch (e) {
    // exit the loop
    break; 
  }
}

(Note that the loop above will only terminate if the code throws an error.)

while( someOuterLoopCondition ) {

    var m = 0;
    var innerLoopOK = true;
    while( innerLoopOK ) {

        try {

            // your original inner-loop body goes here

        } catch e {
            innerLoopOK = false;
        }

        m++;
    }
}

Or:

while( someOuterLoopCondition ) {
    for( var m = 0; m < upperBound; m++ ) {
        try {
            // your original inner-loop body goes here
        } catch e {
            break; // breaks inner-loop only
        }
    }
}