Utilizing the power of combined variables in Javascript

Question

Utilizing the power of combined variables in Javascript

Is there a method to incorporate variables in each loop of a javascript loop? For instance, if I were to insert this code into a loop

if (e1) {item_text += '{id:"' + id[1] + '",lvl:' + e1lvl + '},<wbr>'} 
if (e2) {item_text += '{id:"' + id[2] + '",lvl:' + e2lvl + '},<wbr>'} // and so forth

and attempt something like

for (n = 0; n < id.length; n++) { 
  if (e/*concat var e w/var n?*/) { 
    item_text += '{id:"' + id[1] + '",lvl:' + e/*concat var e w/var n?*/lvl + '},<wbr>'
  }
}

Is there a way to modify the number in the variable names (e1 -> e2 etc) during each loop iteration, or do I need to continue writing it out line by line?

javascript variables concatenation

Answer 1

Answer №1

It is technically feasible, yet strongly advised against, to utilize eval in order to generate the variable name:

const e1lvl1 = 'foo';
const e2lvl1 = 'bar';
for (let i = 1; i < 3; i++) {
  console.log(eval('e' + i + 'lvl1'));
}

However, a more preferable approach would be to enhance your script's framework so that this workaround is not required: organize each e#lvl within an array, and then retrieve the correct index from the array during each iteration:

const elvl = [
  'foo',
  'bar'
];
let item_text = '';
for (let i = 0; i < elvl.length; i++) {
  item_text += 'lvl: ' + elvl[i] + '\n';
}
console.log(item_text);

Answer 2

It is technically feasible, yet strongly advised against, to utilize eval in order to generate the variable name:

const e1lvl1 = 'foo';
const e2lvl1 = 'bar';
for (let i = 1; i < 3; i++) {
  console.log(eval('e' + i + 'lvl1'));
}

However, a more preferable approach would be to enhance your script's framework so that this workaround is not required: organize each e#lvl within an array, and then retrieve the correct index from the array during each iteration:

const elvl = [
  'foo',
  'bar'
];
let item_text = '';
for (let i = 0; i < elvl.length; i++) {
  item_text += 'lvl: ' + elvl[i] + '\n';
}
console.log(item_text);

Answer 3

Answer №2

Make the most of arrays and objects in your JavaScript code! Instead of cluttering your code with variables like e1, e1l, e2..., consider organizing them into an object or array for easier access. Utilize JavaScript functions to ensure all elements meet specific conditions.

function submit() {
    var elements = {};
    var index = 28;
    
    for (var i = 0; i <= 24; i++) {
      elements[i] = {};
      elements[i].key = document.getElementById(`ench${i}`).checked;
      elements[i].value = $.trim(form.elements[index].value);
      
      index += 2;
    }
    
    // Check condition
    if (Object.values(elements).some(item => item.key)) {
      // At least one checked item is true
    }
    
}

Answer 4

Make the most of arrays and objects in your JavaScript code! Instead of cluttering your code with variables like e1, e1l, e2..., consider organizing them into an object or array for easier access. Utilize JavaScript functions to ensure all elements meet specific conditions.

function submit() {
    var elements = {};
    var index = 28;
    
    for (var i = 0; i <= 24; i++) {
      elements[i] = {};
      elements[i].key = document.getElementById(`ench${i}`).checked;
      elements[i].value = $.trim(form.elements[index].value);
      
      index += 2;
    }
    
    // Check condition
    if (Object.values(elements).some(item => item.key)) {
      // At least one checked item is true
    }
    
}

Answer 5

Answer №3

I highly recommend updating your code to utilize arrays.

Regarding your query, given that your e1 and e1lvl variables are in the global scope, you can retrieve them using the following method:

window["e1"]
window["e1lvl"]

Feel free to experiment with this approach:

for (i = 0; i < id.length; i++) { 
  if (window["e" + i]) { 
    item_data += '{id:"' + id[i] + '",lvl:' + window["e" + i + "lvl"] + '},<wbr>';
  }
}

Answer 6

I highly recommend updating your code to utilize arrays.

Regarding your query, given that your e1 and e1lvl variables are in the global scope, you can retrieve them using the following method:

window["e1"]
window["e1lvl"]

Feel free to experiment with this approach:

for (i = 0; i < id.length; i++) { 
  if (window["e" + i]) { 
    item_data += '{id:"' + id[i] + '",lvl:' + window["e" + i + "lvl"] + '},<wbr>';
  }
}

Utilizing the power of combined variables in Javascript

Answer №1

Answer №2

Answer №3

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