CODEWITHSUNDEEP
javascriptarraysobject
Ninad Bondre
Ninad Bondre

Reputation: 57

how to access nested array/object and filter non empty elements of array like NaN,null,0

Below is the array of objects. what we have to do is to

  1. create an array that contains all the non-empty elements of array arr with value not equal to null, NaN, 'undefined' and 0
  2. remaining in the second array
var arr = [
  { id: 15 },
  { id: -1 },
  { id: 0 },
  { id: 3 },
  { id: 12.2 },
  {},
  { id: null },
  { id: NaN },
  { id: "undefined" }
];

what I have tried is


var obj1 = {};
 var prop1 = [];
 var prop2 = [];
  arr.forEach(el=>{
      if(el.id!==0 || el.id!==null || el.id!==undefined || el.id!==NaN){
          prop1.push(el)
      }
      else{
          prop2.push(el)
      }
  })
  console.log(prop1)
  
  console.log(prop2)

but it is not working

output I receive -

1] [{id: 15}, {id: -1}, {id: 0}, {id: 3}, {id: 12.2}, {}, {id: null}, {id: null}, {id: "undefined"}]

2] []

expected -

1] [{id: 0}, {id: null}, {id: "undefined"}]

2] [{id: 15}, {id: -1}, {id: 3}, {id: 12.2}]

Upvotes: 0

Views: 898

Answers (3)

mickl
mickl

Reputation: 49945

You can cast to boolean (!el.id) which will handle most cases and you have to deal with "undefined" separately:

var arr = [
  { id: 15 },
  { id: -1 },
  { id: 0 },
  { id: 3 },
  { id: 12.2 },
  {},
  { id: null },
  { id: NaN },
  { id: "undefined" }
];

var obj1 = {};
 var prop1 = [];
 var prop2 = [];
  arr.forEach(el=>{
      if(!el.id || el.id === "undefined"){
          prop1.push(el)
      }
      else{
          prop2.push(el)
      }
  })

  console.log(prop1);
  console.log(prop2);
  console.log(prop1.length);
  console.log(prop2.length);

Upvotes: 2

LearningEveryday
LearningEveryday

Reputation: 584

Try this:

var arr = [
  { id: 15 },
  { id: -1 },
  { id: 0 },
  { id: 3 },
  { id: 12.2 },
  {},
  { id: null },
  { id: NaN },
  { id: "undefined" }
];
let filterArray = arr.filter((el) => {return !el.id || [0,null,"undefined",NaN].includes(el.id)});
console.log(filterArray);
let filterArray1 = arr.filter((el) => {return el.id && ![0,null,"undefined",NaN].includes(el.id)});
console.log(filterArray1);

Upvotes: 1

Markus Anetz
Markus Anetz

Reputation: 80

why does it not work? Is the ordering incorrect or is there a JavaScript error?

The code looks fine at the first glance, you may use if (!el.id), which checks if the id is "falsy" (0, null, undefined, NaN, false)

You may also have a look at the methods "map" and "filter", https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Array/map

Upvotes: 0

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