对象数组，某些对象包含另一个数组，需要通过包含数组的对象中的值对其进行过滤

Question

Sorry for the long title question didn't know how to properly formulate my question.

So this is the question, I got an array which stores objects, and within those objects there's another array with the key tags and which is an array that gets filled with tags.

Object:

var arr = new Array;

arr[0] = {
            "like": 0,
            "dislike": 0,
            "answer": "body",
            "tags" : ["offline", "facebook"],
            "comments" : []
        };

arr[1] = {
            "like": 0,
            "dislike": 0,
            "answer": "body",
            "tags" : ["school", "online"],
            "comments" : []
        };

arr[2] = {
        "like": 0,
        "dislike": 0,
        "answer": "body",
        "tags" : ["school", "offline"],
        "comments" : []
    };

The [0], [1] indexes respresent and ID, but that isn't really important here.

The problem is when I try to filter it with(I know it only tries to filter arr[0] atm but I will write a loop so it goes through all the indexes):

var toFind = "offline";

var filtered = arr[0].filter(function(el) {
  return el.tags === toFind;
});

console.log(filtered);

It says arr[0].filter is not a function, but got no idea why it thinks arr[0] should be taken into account as a function.

When I remove the [0] it gives back a blank array...

So my question is how can I get the .filter function to give back the complete object based on tags in the tags array. So that if I search for the tag "school" it gives back arr[1] and arr[2], the complete objects.

Hope I my question is crystal clear and that I provided enough information. If you guys need anymore information, feel free to ask me for it. Or if you want me to clarify things, just ask :)

Hope you guys can help me!

Answer 1

Refering to the documention : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter?v=control

you shall use :

var arr = new Array;

arr[0] = {
            "like": 0,
            "dislike": 0,
            "answer": "body",
            "tags" : ["offline", "facebook"],
            "comments" : []
        };


var toFind = "offline";
//I'm filtering on arr[0].tags directly !! 
var filtered = arr[0].tags.filter(function(el) { 

  return el === toFind;
});

console.log(filtered);

Answer 2

Like has been said, arr[0] points to an object, which doesn't have a filter method. You need to call filter on the array itself

 var tagToFind = "school"; var arr = new Array; arr[0] = { "like": 0, "dislike": 0, "answer": "body", "tags" : ["offline", "facebook"], "comments" : [] }; arr[1] = { "like": 0, "dislike": 0, "answer": "body", "tags" : ["school", "online"], "comments" : [] }; arr[2] = { "like": 0, "dislike": 0, "answer": "body", "tags" : ["school", "offline"], "comments" : [] }; var filtered = arr.filter(function(item){ return item.tags && //to account for undefined tags properties item.tags.includes(tagToFind); //if you're supporting IE you will need to look and check each element instead }); console.log(filtered); 

Answer 3

If I am interpreting your question correctly, it appears that you want something along the lines of

arr.forEach((a) => {
    if (a["tags"].includes(toFind))
        console.log(a);
});

This will loop through each element of arr and check that the tags array contains toFind (and prints out the object if it does).

Answer 4

if you want to do it for the whole array then try this

 var arr = new Array;
 arr[0] = {
        "like": 0,
        "dislike": 0,
        "answer": "body",
        "tags" : ["offline", "facebook"],
        "comments" : []
    };

  arr[1] = {
        "like": 0,
        "dislike": 0,
        "answer": "body",
        "tags" : ["school", "online"],
        "comments" : []
    };

   arr[2] = {
    "like": 0,
    "dislike": 0,
    "answer": "body",
    "tags" : ["school", "offline"],
    "comments" : []
};
var filtered = arr.filter(function(el) {
  return el.tags.find(function (entity){
    return entity===toFind;
  });
});

 console.log(filtered);