jQuery using values from inside each function

Question

The code I wrote below works, but the variables I named within the each function are not defined after the function completes.

jQuery.each($myObject, function(i, val) {
  ce = $(this).attr('class');
  if (i === 0) {
    step1complete = true;
    if (/incomplete/i.test(ce)) {
      var step1complete = false
    }
    console.log('step1' + step1complete);
  } else if (i === 1) {
    step2complete = true
    if (/incomplete/i.test(ce)) {
      var step2complete = false
    }
    console.log('step2' + step2complete);
  } else if (i === 2) {
    step3complete = true
    if (/incomplete/i.test(ce)) {
      var step3complete = false
    }
    console.log('step3' + step3complete);
  }
});

if (step1complete === true && step2complete == false && step3 == false) {
  console.log('Youre Just Starting Out I see');
} else {
  console.log('You got one step done now theres more!');
}

However, its saying the variables I set in the each function are not defined even though I see them in the console during the loop.

@DamienGold If you understand JavaScript, the above code is enough. :) — Praveen Kumar Purushothaman
– Praveen Kumar Purushothaman, Commented Apr 7, 2018 at 23:21
@DamienGold Oh sorry. But I was able to find the issue with his code, the moment I saw it. That seems to be the full code. What exactly were you expecting to see? :) Just curious to know. — Praveen Kumar Purushothaman
– Praveen Kumar Purushothaman, Commented Apr 7, 2018 at 23:24

Praveen Kumar Purushothaman · Accepted Answer · 2018-04-07 23:20:13Z

1

Don't use var as it will scope it inside the function that is enclosed. Instead, bring them out, just the var part.

var step1complete;
var step2complete;
var step3complete;
jQuery.each($myObject, function(i, val) {
  ce = $(this).attr('class');
  if (i === 0) {
    step1complete = true;
    if (/incomplete/i.test(ce)) {
      step1complete = false
    }
    console.log('step1' + step1complete);
  } else if (i === 1) {
    step2complete = true
    if (/incomplete/i.test(ce)) {
      step2complete = false
    }
    console.log('step2' + step2complete);
  } else if (i === 2) {
    step3complete = true
    if (/incomplete/i.test(ce)) {
      step3complete = false
    }
    console.log('step3' + step3complete);
  }
});

if (step1complete === true && step2complete == false && step3 == false) {
  console.log('Youre Just Starting Out I see');
} else {
  console.log('You got one step done now theres more!');
}

If you don't want to pollute the global scope, use an IIFE:

(function () {
  var step1complete;
  var step2complete;
  var step3complete;
  jQuery.each($myObject, function(i, val) {
    ce = $(this).attr('class');
    if (i === 0) {
      step1complete = true;
      if (/incomplete/i.test(ce)) {
        step1complete = false
      }
      console.log('step1' + step1complete);
    } else if (i === 1) {
      step2complete = true
      if (/incomplete/i.test(ce)) {
        step2complete = false
      }
      console.log('step2' + step2complete);
    } else if (i === 2) {
      step3complete = true
      if (/incomplete/i.test(ce)) {
        step3complete = false
      }
      console.log('step3' + step3complete);
    }
  });

  if (step1complete === true && step2complete == false && step3 == false) {
    console.log('Youre Just Starting Out I see');
  } else {
    console.log('You got one step done now theres more!');
  }
})();

Definition:

IIFE (Immediately Invoked Function Expression) is a JavaScript function that runs as soon as it is defined. It is a design pattern which is also known as Self-Executing Anonymous Function and contains two major parts. The first is the anonymous function with lexical scope enclosed within the Grouping Operator (). This prevents accessing variables within the IIFE idiom as well as polluting the global scope.

edited Apr 7, 2018 at 23:20

answered Apr 7, 2018 at 23:18

Praveen Kumar Purushothaman

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11 Comments

weekapaug Over a year ago

What does use a closure mean? nvm i see now thanks for example!

Praveen Kumar Purushothaman Over a year ago

@weekapaug I have updated it to IIFE. Check out the link.

Praveen Kumar Purushothaman Over a year ago

@weekapaug IIFE (Immediately Invoked Function Expression) is a JavaScript function that runs as soon as it is defined. It is a design pattern which is also known as Self-Executing Anonymous Function and contains two major parts. The first is the anonymous function with lexical scope enclosed within the Grouping Operator (). This prevents accessing variables within the IIFE idiom as well as polluting the global scope.

weekapaug Over a year ago

Great links & examples! cant wait to dig in, thanks!

weekapaug Over a year ago

A quick newbie question on this. is var mynewvar the same as saying mynewvar=true? even though its not set to anything specific?

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