Filter Array From Another Array in ES6

Question

I need to filter out contacts from data. Whatever data gets from contacts should be filtered out in remainingData

contacts = [
    {
        "contact_id": 12,
        "f_name": "RARA",
    },
    {
        "contact_id": 14,
        "f_name": "BABA",
    },
    {
        "contact_id": 15,
        "f_name": "CACA",
    },
    {
        "contact_id": 14,
        "f_name": "DADA",
    },
]


data = [
    {
        "contact_id": 12,
        "f_name": "RARA",
    },
     {
        "contact_id": 14,
        "f_name": "DADA",
    },
]


remainingData = [
     {
        "contact_id": 14,
        "f_name": "BABA",
    },
    {
        "contact_id": 15,
        "f_name": "CACA",
    },
]

CODE

const remainingData = contacts.filter(item => item.contact_id !== data.contact_id)

@Ouroborus. Its different. Its array of object vs array of objects — Joseph
– Joseph, Commented Aug 1, 2021 at 11:19
@Joseph see Array.prototype.filter() and Arrow function expressions docs... — Lluser
– Lluser, Commented Aug 1, 2021 at 11:26

Nitheesh · Accepted Answer · 2021-08-01 11:35:09Z

2

Solution using array.filter

contacts = [
    { "contact_id": 12, "f_name": "RARA" },
    { "contact_id": 14, "f_name": "BABA" },
    { "contact_id": 15, "f_name": "CACA" },
    { "contact_id": 14, "f_name": "DADA" },
]


data = [ 
    { "contact_id": 12, "f_name": "RARA" },
    { "contact_id": 14, "f_name": "DADA" },
]

const remainingData = contacts.filter(item => !data.find((node) => item.contact_id === node.contact_id && item.f_name === node.f_name));

console.log(remainingData);

Alternative solution using array.reduce

contacts = [
    { "contact_id": 12, "f_name": "RARA" },
    { "contact_id": 14, "f_name": "BABA" },
    { "contact_id": 15, "f_name": "CACA" },
    { "contact_id": 14, "f_name": "DADA" },
]


data = [ 
    { "contact_id": 12, "f_name": "RARA" },
    { "contact_id": 14, "f_name": "DADA" },
]


const remainingData = contacts.reduce((acc, curr) => {
    const searchNode = data.find((node) => node.contact_id === curr.contact_id && node.f_name === curr.f_name);
    if(!searchNode) {
        acc.push(curr);
    }
    return acc;
}, []);

console.log(remainingData);

If you want the result of filtration back in the contacts variable just assign back the result of filtrarion to the same variable like

contacts = contacts.filter(item => !data.find((node) => item.contact_id === node.contact_id && item.f_name === node.f_name))

edited Aug 1, 2021 at 11:35

answered Aug 1, 2021 at 11:25

Nitheesh

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1 Comment

Nitheesh Over a year ago

If you are performing arrayfilter or array.reduce just re assign the contacts variable with the response of filtration like

contacts = contacts.filter(item => !data.find((node) => item.contact_id === node.contact_id && item.f_name === node.f_name))

LeeLenalee · Accepted Answer · 2021-08-01 11:25:42Z

0

You can map your array of objects containing the ids to a normal array with only the ID's where you can check against

let contacts = [{
    "contact_id": 12,
    "f_name": "RARA",
  },
  {
    "contact_id": 14,
    "f_name": "BABA",
  },
  {
    "contact_id": 15,
    "f_name": "CACA",
  },
  {
    "contact_id": 14,
    "f_name": "DADA",
  },
]

let data = [{
    "contact_id": 12,
    "f_name": "RARA",
  },
  {
    "contact_id": 14,
    "f_name": "DADA",
  },
]

let filtered = contacts.filter(item => (data.map(x => (x.contact_id)).some(id => (id === item.contact_id))))

console.log(filtered)

answered Aug 1, 2021 at 11:25

LeeLenalee

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Comments

Alwani Anis · Accepted Answer · 2021-08-01 12:11:27Z

0

To compare two objects we need to compare unique field (if exist) , so if contact_id is unique:

const remainingData = contacts.filter(item => data.find((node) => item.contact_id === node.contact_id )=='undefined');

Otherwise we should compare the two objects after converting them to json string , so :

const remainingData = contacts.filter(item => data.find((node) => JSON.stringify(item) === JSON.stringify(node))=='undefined');

edited Aug 1, 2021 at 12:11

answered Aug 1, 2021 at 11:52

Alwani Anis

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