I have an empty array
const someArray = []
and then I have another array of 2 objects (can vary)
let users = [
{
id: '2c919536-ccb5-4c3b-b599-36dc716b7478',
name: 'John Doe',
age: 50,
},
{
id: '2c919536-ccb5-4c3b-b599-36dc716b7478',
name: 'Jane Doe',
age: 45,
},
];
the id key which make users unique.
As you can see I have 2 users with same id I only want to add the first one. What I did so far
users.forEach((user) => {
if (!someArray.includes(user.id)) {
someArray.push(user);
}
});
// OTHER METHOD I USED
users.forEach((user) => {
if (someArray.some((element) => element.id !== user.id)) {
someArray.push(user);
}
});
The first method appending both elements even thier id's are same and the second method is doing nothing or is not appending anything.
You could keep a map with the ids that you already added, and only add it if the key is missing:
const ids = {};
users.forEach(user => {
if (!ids[user.id]) {
someArray.push(user);
ids[user.id] = true;
}
})
using reduce would work for your case
let users = [{
id: '2c919536-ccb5-4c3b-b599-36dc716b7478',
name: 'John Doe',
age: 50,
},
{
id: '2c919536-ccb5-4c3b-b599-36dc716b7478',
name: 'Jane Doe',
age: 45,
},
{
id: '8c919536-ccb5-4c3b-b599-36dc716b7478',
name: 'Jane Doe',
age: 45,
},
];
var result = users.reduce((prev, curr) => {
if (prev.find(i => i.id == curr.id)) return prev
return [...prev, curr]
}, [])
console.log(result);