So I have data like the following:

[
     {
      "id": 0,
      "title": "happy dayys",
      "owner": {"id": "1", "username": "dillonraphael"},
      "tags": [{"value": "Art", "label": "Art"}],
      "items": []
     },
     {
      "id": 1,
      "title": "happy dayys",
      "owner": {"id": "1", "username": "dillonraphael"},
      "tags": [{"value": "Architecture", "label": "Architecture"}],
      "items": []
     },
]

I'm trying to filter through an array and only return if the tags array contains a value that is == to another string.

This is what I came up with but still seems to be sending back the whole array:

const tagMoodboards = _moodboards.filter(mb => { return mb.tags.filter(t => t.value == name) })

So I have data like the following:

[
     {
      "id": 0,
      "title": "happy dayys",
      "owner": {"id": "1", "username": "dillonraphael"},
      "tags": [{"value": "Art", "label": "Art"}],
      "items": []
     },
     {
      "id": 1,
      "title": "happy dayys",
      "owner": {"id": "1", "username": "dillonraphael"},
      "tags": [{"value": "Architecture", "label": "Architecture"}],
      "items": []
     },
]

I'm trying to filter through an array and only return if the tags array contains a value that is == to another string.

This is what I came up with but still seems to be sending back the whole array:

const tagMoodboards = _moodboards.filter(mb => { return mb.tags.filter(t => t.value == name) })

• javascript
• arrays
• ecmascript-6

• You need to use map() to return clones with filtered arrays. – SLaks Commented Jul 2, 2018 at 2:16
• 2 What is the desired result and what's in mb.tags? I don't follow what the objective is. – jfriend00 Commented Jul 2, 2018 at 2:17
• 2 If i understand the question right, the inner part looks more like an application for some. – ASDFGerte Commented Jul 2, 2018 at 2:19
• 2 mb.tags.filter(t => t.value == name) will always be an array, so it’s always truthy, so the outer filter is equivalent to just const tagMoodboards = _moodboards.filter(mb => { return true }). – Sebastian Simon Commented Jul 2, 2018 at 2:20
• 1 Although filter() not best approach on the inner .... return the length of the resultant array instead of the array itself – charlietfl Commented Jul 2, 2018 at 2:22

2 Answers 2

You don't want a filter inside a filter - rather, inside the filter, check if some of the tags objects have the .value property that you want

const _moodboards = [
     {
      "id": 0,
      "title": "happy dayys",
      "owner": {"id": "1", "username": "dillonraphael"},
      "tags": [{"value": "Art", "label": "Art"}],
      "items": []
     },
     {
      "id": 1,
      "title": "happy dayys",
      "owner": {"id": "1", "username": "dillonraphael"},
      "tags": [{"value": "Architecture", "label": "Architecture"}],
      "items": []
     },
];
const name = 'Architecture';
console.log(_moodboards.filter(({ tags }) => (
  tags.some(({ value }) => value === name)
)));

To use filter() you need something that will return true or false -- i.e. a Boolean. That should be the first place you start. So given an object like

{
 "id": 0,
 "title": "happy dayys",
 "owner": {"id": "1", "username": "dillonraphael"},
 "tags": [{"value": "Art", "label": "Art"}],
 "items": []
},

if you want to decide whether or not that should be used, you might try Array.some() on the tags array. This will return a boolean.

let tags = [{"value": "Art", "label": "Art"}]

console.log(tags.some(tag => tag.value = "Art")) // true

With that in hand, you can now use filter() and some() together. some() will return true or false for each item in the array and that will determine whether it's filtered or not:

let arr =  [{"id": 0,"title": "happy dayys","owner": {"id": "1", "username": "dillonraphael"},"tags": [{"value": "Art", "label": "Art"}],"items": []},{"id": 1,"title": "happy dayys","owner": {"id": "1", "username": "dillonraphael"},"tags": [{"value": "Architecture", "label": "Architecture"}],"items": []},]

console.log(arr.filter(obj => obj.tags.some(o => o.value == 'Art') ))