Filter an array of object using filter array

Question

I'm trying to filter an array using 2 criteria : one is straigthforward (==1) and the other is an array. In the below example, i would want to filter : level = 0 or name comprises in ['B','S']

[
{id: 1, level: 0, name: 'A'},
{id: 2, level: 1, name: 'B'},
{id: 3, level: 1, name: 'S'},
{id: 4, level: 0, name: 'A'},
{id: 5, level: 0, name: 'S'},
{id: 6, level: 1, name: 'A'},
{id: 7, level: 0, name: 'B'}, ]

so the result would be :

[
{id: 1, level: 0, name: 'A'},
{id: 2, level: 1, name: 'B'},
{id: 3, level: 1, name: 'S'},
{id: 4, level: 0, name: 'A'},
{id: 5, level: 0, name: 'S'},
{id: 7, level: 0, name: 'B'}, ]

As i'm limited with ecmaScript-5 i cannot use .includes that would have helped here.

Also, i would like to stick to .filter function.

Any idea how to achieve this ?

thanks

`a.filter(t => (t.name == 'A' || t.name == 'B') || t.id == 1)` — AKT, Jan 02 '23 at 12:40

gavgrif · Answer 1 · 2023-01-02T12:44:31.230

A simple loop would achieve this - and push the matching items into a new array that then has the desired items.

I have avoided the newer more exciting ways of doing this for the old school var and forEach approach to match your ecma-5 requirement.

var arr = [
{id: 1, level: 0, name: 'A'},
{id: 2, level: 1, name: 'B'},
{id: 3, level: 1, name: 'S'},
{id: 4, level: 0, name: 'A'},
{id: 5, level: 0, name: 'S'},
{id: 6, level: 1, name: 'A'},
{id: 7, level: 0, name: 'B'}, ]

var newArr = [];

arr.forEach(function(item) {
  if(item.level === 1 || (item.name === 'A' || item.name ==='B')) {
   newArr.push(item)
  }
})


console.log(newArr);

//gives[
  //{id: 1,level: 0, name": "A"},
  //{id: 2, level: 1, name: "B"},
  //{id: 3, level: 1, name: "S"},
  //{id: 4, level: 0, name: "A"},
  //{id: 6, level: 1, name: "A"},
  //{id: 7, level: 0, name: "B"}]

score 2 · Accepted Answer · edited Jan 02 '23 at 12:55

2

Using ecmaScript-5 you can do:

var arr = [{ id: 1, level: 0, name: 'A' },{ id: 2, level: 1, name: 'B' },{ id: 3, level: 1, name: 'S' },{ id: 4, level: 0, name: 'A' },{ id: 5, level: 0, name: 'S' },{ id: 6, level: 1, name: 'A' },{ id: 7, level: 0, name: 'B' },]

var result = arr.filter(function (obj) {
  return obj.level === 1 || ['B', 'S'].indexOf(obj.name) > -1;
})


console.log(result)

edited Jan 02 '23 at 12:55

Nick Parsons

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answered Jan 02 '23 at 12:46

Yosvel Quintero

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@NickParsons thank you for your comment.. Refactored code to ecmaScript-5 – Yosvel Quintero Jan 02 '23 at 12:52
thanks, this works well ! (by the way the >-1 allows for an empty filter array (['B', 'S']). – Sebastien Chemouny Jan 02 '23 at 13:39

Joan Lara · Answer 3 · 2023-01-02T12:43:58.167

1

You can use the Array.prototype.filter() method along with the Array.prototype.indexOf() method to filter the array based on your criteria:

const array = [
  {id: 1, level: 0, name: 'A'},
  {id: 2, level: 1, name: 'B'},
  {id: 3, level: 1, name: 'S'},
  {id: 4, level: 0, name: 'A'},
  {id: 5, level: 0, name: 'S'},
  {id: 6, level: 1, name: 'A'},
  {id: 7, level: 0, name: 'B'},
];

var names = ['B', 'S'];

var result = array.filter(item => item.level === 0 || names.indexOf(item.name) !== -1);

console.log(result)

edited Jan 02 '23 at 12:43

answered Jan 02 '23 at 12:38

Joan Lara

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You should probably avoid using `const` and arrow functions in your answer if you want to meet the "ecmascript 5" only requirement of the question. – Nick Parsons Jan 02 '23 at 12:42
@NickParsons You are right, I edited my answer. – Joan Lara Jan 02 '23 at 12:44
I guess you forgot the arrow function (as that would need to be a regular function expression with a `return` for it to be es5 compatible) – Nick Parsons Jan 02 '23 at 12:45

score 1 · Answer 4 · answered Jan 02 '23 at 12:39

const arr = [
  { id: 1, level: 0, name: 'A' },
  { id: 2, level: 1, name: 'B' },
  { id: 3, level: 1, name: 'S' },
  { id: 4, level: 0, name: 'A' },
  { id: 5, level: 0, name: 'S' },
  { id: 6, level: 1, name: 'A' },
  { id: 7, level: 0, name: 'B' },
];

const newArr = arr.filter(
  item => item.level === 0 || item.name === 'B' || item.name === 'S'
);

console.log(newArr);

Filter an array of object using filter array

4 Answers4