Pass parameter in FILTER of a Javascript array

Question

I need to pass a parameter to an external function I want to create for a filter array, but do not know how to do. Example: This code already works:

const myArray = [
    { "name": "nome1" },
    { "name": "nome2" },
    { "name": "nome3" },
    { "name": "nome4" },
    { "name": "nome5" }
];

let qParam = myRequest.query.myParam;

// Retorna o item do array cujo campo "name" corresponde a "qParam"
const user = myArray.filter(u => qParam === u.name)[0];

Now I want to do something like this below, but it doesn’t work because I can’t get through qParam by parameter and this variable is also outside the scope accessible by myFunction. How do I fix it:

function myFunction(value, qParam) {
    return value === qParam;
}
const user = myArray.filter(myFunction);

Answer 1

What you can do is use the concept of decorator, which simplistically is a function that returns another function, applying some treatment on this. In this case, the decorator would receive the parameter name and return a function that performs the name filter relative to the value of name:

function filterByName(name) {
  return function filter(value) {
      return value.name === name;
  }
}

That is, to generate a filter that uses as reference the value of qParam, just do:

const user = myArray.filter( filterByName(qParam) )[0];

Take the example:

const myArray = [
    { "name": "nome1" },
    { "name": "nome2" },
    { "name": "nome3" },
    { "name": "nome4" },
    { "name": "nome5" }
];

let qParam = "nome3";

function filterByName(name) {
  return function filter(value) {
      return value.name === name;
  }
}

const user = myArray.filter(filterByName(qParam))[0];

console.log(user);