Javascript array filter based on 2nd level array key

Question

I am trying to filter an array that has 2 levels of children. I am able to filter the 1st level of the array but not the 2nd. I am trying to return an array that has a specific email under collaborators. Here is the structure

and here is the code. This code does not match email so return all the items in the array

this.firebase.list('/todo').
map(data => data.filter((e) => {
    return e.collaborators.filter((x) => {
        return x.email == email;
    });
}));

Sample JSON:

{
  "todo" : {
    "-Kee7m7WkNDhrbX_0Ycb" : {
      "collaborators" : [ {
        "email" : "test@gmail.com",
        "name" : "test"
      },
      {
        "email" : "test1@gmail.com",
        "name" : "test1"
      } ],
      "created_at" : 1488913112569,
      "created_by" : "test@gmail.com",
      "preview" : "",
      "title" : "test",
      "updated_at" : 1488913112569
    },
    "-Kee7m7WkNDhrbX_0Ycb" : {
      "collaborators" : [ {
        "email" : "test@gmail.com",
        "name" : "test"
      },
      {
        "email" : "test2@gmail.com",
        "name" : "test2"
      } ],
      "created_at" : 1488913112569,
      "created_by" : "test@gmail.com",
      "preview" : "",
      "title" : "test",
      "updated_at" : 1488913112569
    }
  }
}

Required output:

Only the first array which has an email test1@gmail.com

Answer 1

I'm not sure what's your desired output but hope that the following example helps you.

Hope this helps.

var obj = {
  "todo" : {
    "-Kee7m7WkNDhrbX_0Yca" : {
      "collaborators" : [ {
        "email" : "test@gmail.com",
        "name" : "test"
      },
      {
        "email" : "test1@gmail.com",
        "name" : "test1"
      } ],
      "created_at" : 1488913112569,
      "created_by" : "test@gmail.com",
      "preview" : "",
      "title" : "test",
      "updated_at" : 1488913112569
    },
    "-Kee7m7WkNDhrbX_0Ycb" : {
      "collaborators" : [ {
        "email" : "test@gmail.com",
        "name" : "test"
      },
      {
        "email" : "test2@gmail.com",
        "name" : "test2"
      } ],
      "created_at" : 1488913112569,
      "created_by" : "test@gmail.com",
      "preview" : "",
      "title" : "test",
      "updated_at" : 1488913112569
    }
  }
};

var email = "test1@gmail.com";
var result = [];

for(var key in obj["todo"]) {
   obj["todo"][key].collaborators.filter((x) => {
     if ( x.email == email )
       result.push( obj["todo"][key] );
  });
}

console.log(result);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Answer 2

You want the filter callback to return a boolean value, not an array. So use some or every instead of filter on the collaborators.