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V0LT3RR4
Asked: 2020-04-21 08:19:46 +0800 CST 2020-04-21 08:19:46 +0800 CST

How to replace elements of an Array by those of another under a certain condition in Javascript?

  • 772

I have two arrangements:

const myArray1 = [{updatedProp: 'prop'}, {updatedProp2: 'prop2'}];
const myArray2 = [{oldProp: 'oldProp'}, 'Una cadena', {oldProp2: 'oldProp2'}];

How do I make it so that under the condition that if the element is a Object, it must be replaced by the new one in the order the arrays are initially found?

The result I expect is:

[updatedProp, 'A string', updatedProp2]

That is, something like:

const myUpdateArray = myArray2.map(element => {
  if(typeof element === 'object'){
    return //elemento actualizado
  }
});
javascript

3 Answers

  1. Best Answer

    const myArray1 = [{updatedProp: 'prop'}, {updatedProp2: 'prop2'}];
const myArray2 = [{oldProp: 'oldProp'}, 'Una cadena', {oldProp2: 'oldProp2'}];

let contador = 0;

let resultado = myArray2.map(e => {
 // si es objeto retorna un elemento de myArray1 en la posicion
 // contador
 if(typeof e === 'object') return myArray1[contador++];
 // si no es objeto retorna la cadena
 return e;
 
});

console.log(resultado);

    • 2

  2. To solve this simply create an index starting at 0, map the old array and if the property is an object ( typeof p === 'object') return the update array property at the position of the current index and then increment the index, if not an object ( the current item of the old array) the value of index will not be increased so the position will be reserved for when it is an object again, all this is taking into account that you ask for a replacement in the order that the arrays are initially found.

    Look at the example :

    const myArray1 = [{updatedProp: 'prop'}, {updatedProp2: 'prop2'}];
const myArray2 = [{oldProp: 'oldProp'}, 'Una cadena', {oldProp2: 'oldProp2'}];

replace(myArray1, myArray2, res => {
  console.log(res)
  document.querySelector("pre").innerHTML = JSON.stringify(res, null, 2)
})

function replace(update, old, cb) {
  let iR = 0;
  var newArr = old.map(p => {
    iR = typeof p === 'object' ? iR +1 : iR;
    return typeof p === 'object' ? update[iR-1] : p;
  })
  return cb(newArr)
}
    <pre></pre>

    I hope it helps, greetings.

    • 2

  3. I turned the array with the updated elements upside down and replaced the old elements with the updated ones at the object's position whenever the condition required it by popping them out in order with pop().

    const myArray1 = [{updatedProp: 'prop'}, {updatedProp2: 'prop2'}].reverse();
const myArray2 = [{oldProp: 'oldProp'}, 'Una cadena', {oldProp2: 'oldProp2'}];

const myUpdateArray = myArray2.map(element => {
  return typeof element === 'object' ? myArray1.pop() : element;
});

console.log(myUpdateArray);

    • 2