Better way to access nested attributes in JavaScript

user_5127346 0
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I have this function in which I want to access nested attributes from passed arguments inside the function.

var objectsArr = [
  {nestedobj:{property:'1'}},
  {nestedobj:{property:'3'}},
  {nestedobj:{property:'2'}},
  {nestedobj:{property:'4'}}
];

function sortObjectsArr(objectsArray) {
  if (arguments.length == 2) {
    objectsArray.sort((a,b) => a[arguments[1]] - b[arguments[1]]);
  }

  if (arguments.length == 3) {
    objectsArray.sort((a,b) => a[arguments[1]][arguments[2]] - b[arguments[1]][arguments[2]]);
  }

  if (arguments.length == 4) {
    objectsArray.sort((a,b) => a[arguments[1]][arguments[2]][arguments[3]] - b[arguments[1]][arguments[2]][arguments[3]]);
  }  
  //and so on and so forth
}


sortObjectsArr(objectsArr, 'nestedobj', 'property');

console.log(objectsArr);

Is there a nicer way to access the attributes from the object? rather than [arguments[1]][arguments[2]][arguments[3]].... ?

object arguments javascript
1 Answers

So I would first take the other args as a rest parameter instead of using the arguments array. Then i wold define a small helper function.

function sortObjectsArr(objectsArray, ...path) {
  objectsArray.sort((a, b) => getFromPath(a, path) - getFromPath(b, path))
}

function getFromPath(obj, path) {
  let r = obj;
  path.forEach(key => { r = r[key]})
  return r
}

let objectsArr = [
  {nestedobj:{property:'1'}},
  {nestedobj:{property:'3'}},
  {nestedobj:{property:'2'}},
  {nestedobj:{property:'4'}}
]; 

sortObjectsArr(objectsArr, 'nestedobj', 'property'); 
console.log(objectsArr);

Finally: avoid using var, use let instead, its old and behaves weirdly (in ways you wouldnt expect). But explaining that is outside of this answer, you can google it.

EDIT: if you want to be really cool you can use the reduce function:

function getFromPath(obj, path) {
     return path.reduce((o, key) => o[key], obj)
}

If this is more readable you need to decide for yourself.

user_89979160
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