Is importing module into the loop a bad practice?

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Good morning guys, I have a javascript module and I import it at the beginning of my main/main code and I run a foreach, still in this main code has loop that calls the methods of the module:

results.forEach(function(result) {
     for(const item of items .......){
        exampleModule.metodo(result, item)
     }
});

So far so good, the problem is that the values of the module are being mixed, the module is not dynamic according to item Y of the result X, it kind of "mess" all over...

I thought of a way to solve, I don’t know if it’s best practice, declare const exampleModule = require('./modules/example.js') within an object and give that object a reference, such as the item ID, since each ID will be unique:

let objetos = {}
results.forEach(function(result) {
     for(const item of items .......){
        objetos[item.id] = require('./modules/example.js')
        objetos[item.id].metodo(result, item)
     }
});

In short, I want each loop item to create an instance of the module without them being interfered with, if I instantiate the module in position item 0, everything in the module should only be used by that item 0, if it is item 1 the same thing, 1 n can change values of the module that is being used by position 0 and so on, is it possible? Can someone please help me?

javascript node.js

  • "the module is not dynamic according to the Y item of the X result" This has become quite confusing and gives the impression that what you are doing can be a XY problem. Why do you need a module to be "dynamic"? And what would those Y and X values be?

  • Describing the general problem you will get only a general answer. Example: "How to build a house?" , "Use blocks and cement, build solid walls". Instead ask something specific and responsive in a useful way: "How to lift a wall using this type of block with such a slope and such height safely?" , answer: "Position the blocks in such format, run this block placement algorithm, do not use this tool because there is such a risk, here is an example running from a wall ready for you to see how it does [link]". See? Too many wide questions don’t help.

  • I’m sorry, I didn’t know how to express myself in the best way. Is that this problem never happened to me, X and Y are loop positions, the item and the result are objects come from the API and are used in the modules

1 answer

1


You should import the module only once. The preference is that it be at the beginning of your file. If you use incremental values within your function, you can use a class to create a new instance with each interaction of loop:

class Exemplo {
  constructor() {
    this.valor = 0;
  }

  funcao(resultado, item) {
    this.valor = resultado + item;
    return this.valor;
  }
}

module.exports = Exemplo;

And would use the above module as follows:

const Exemplo = require('./Exemplo');

// ...
const exemplo = new Exemplo();
for (...) {
   console.log(exemplo.funcao(resultado, item));
}

It may be that your problem is also in relation to asymchronism, but with the information given here it is not possible to suggest a solution.

  • I think you understand my problem, but you see I have a foreach? This foreach calls the results to run in "parallel", if I instantiate the class out of the loop it will end up mixing in the same way

  • @viniciussvl has 2 loops in your question. You can instantiate within the forEach and before the for

  • 1

    Oh yes it is that I saw your code not compared to mine, wonder then Sorach, this can solve the problem for good, thank you for helping me!

  • So @Sorack I did it this way but it doesn’t seem to work, I saw that in your method "function" you pass the parameters, but I’m passing the parameters in the constructor, will it be that?

  • 1

    @viniciussvl do not know, your example is not testable, it is difficult to opine

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