I have an array of objects, and I need to get list with certain property from that array of objects. But i need that list to contain only those values where object was containing another property with certain element. This is very confusing so i made an example. Let's say i have an array with objects.
employees = [
{
n: 'case 1',
date: '2021-05-4',
id: '123',
user: [{name: 'Vlad', id: '1'}, {name: 'Misha', id: '2'}],
isPresent : true,
},
{
caseName: 'case 2',
date: '2021-05-4',
id: '124',
user: [{name: 'Alina', id: '3'}, {name: 'Alex', id: '4'}],
isPresent : true,
},
{
caseName: 'case 3',
date: '2021-05-4',
id: '126',
user: [],
isPresent : false,
},
]
And my task is to get a list of IDs from array of objects, but i need ID only from those objecrs which have isPresent as true.
So i need ['123', '124'].
I could use a loops and conditions and so on. But i wondering is it possible to do with one line ? Something like this:
employees.filter(item => { return item.isPresent === true }))
But i need only IDs not whole objects.
1) You can filter the elements with condition item.isPresent === true and then map over it to get the final result as:
employees
.filter((item) => item.isPresent === true)
.map((o) => o.id);
or you can also do as:
employees.filter((item) => item.isPresent).map((o) => o.id)
const employees = [{
n: 'case 1',
date: '2021-05-4',
id: '123',
user: [{
name: 'Vlad',
id: '1'
}, {
name: 'Misha',
id: '2'
}],
isPresent: true,
},
{
caseName: 'case 2',
date: '2021-05-4',
id: '124',
user: [{
name: 'Alina',
id: '3'
}, {
name: 'Alex',
id: '4'
}],
isPresent: true,
},
{
caseName: 'case 3',
date: '2021-05-4',
id: '126',
user: [],
isPresent: false,
},
]
const result = employees
.filter((item) => item.isPresent === true)
.map((o) => o.id);
console.log(result);2) You can also achieve the same result using reduce as:
employees.reduce((acc, curr) => {
curr.isPresent && acc.push(curr.id);
return acc;
}, []);
const employees = [
{
n: "case 1",
date: "2021-05-4",
id: "123",
user: [
{ name: "Vlad", id: "1" },
{ name: "Misha", id: "2" },
],
isPresent: true,
},
{
caseName: "case 2",
date: "2021-05-4",
id: "124",
user: [
{ name: "Alina", id: "3" },
{ name: "Alex", id: "4" },
],
isPresent: true,
},
{
caseName: "case 3",
date: "2021-05-4",
id: "126",
user: [],
isPresent: false,
},
];
const result = employees.reduce((acc, curr) => {
curr.isPresent && acc.push(curr.id);
return acc;
}, []);
console.log(result);You can use something like this
employees.filter((item) => item.isPresent).map((obj) => obj.id);