How to filter array of object based on another array values using javascript?

Question

I have a simple array of numbers (which for my app represents user Id's). For example...

[1, 2, 3]

I also have an array of objects such as

[
    {Id: 1, FirstName: "Bob", LastName: "Jones", EmailAddress: "bob@bob.com"},
    {Id: 2, FirstName: "Tessa", LastName: "Wong", EmailAddress: "tes@wong.com"},
    {Id: 3, FirstName: "Craig", LastName: "Murray", EmailAddress: "Craig@muz.com"},
    {Id: 4, FirstName: "Bryce", LastName: "Willamson", EmailAddress: "email@me.com"},
    {Id: 5, FirstName: "Tony", LastName: "Ocka", EmailAddress: "toni@oz.com"}
]

What I need to do is match any values that appear in the initial array with they key Id in the second array of objects (and return a new full array of objects containing only matches). So for example in this case, the result I'm looking for is:

[
    {Id: 1, FirstName: "Bob", LastName: "Jones", EmailAddress: "bob@bob.com"},
    {Id: 2, FirstName: "Tessa", LastName: "Wong", EmailAddress: "tes@wong.com"},
    {Id: 3, FirstName: "Craig", LastName: "Murray", EmailAddress: "Craig@muz.com"},
]

Any help would be really appreciated.

Answer 1

It's always good to show your attempt in OP to help fellow users to understand where you are stuck.

You can use "Array.filter" and "includes" for this.

 let arr1 = [1,2,3] let arr2 = [ {Id: 1, FirstName: "Bob", LastName: "Jones", EmailAddress: "bob@bob.com"}, {Id: 2, FirstName: "Tessa", LastName: "Wong", EmailAddress: "tes@wong.com"}, {Id: 3, FirstName: "Craig", LastName: "Murray", EmailAddress: "Craig@muz.com"}, {Id: 4, FirstName: "Bryce", LastName: "Willamson", EmailAddress: "email@me.com"}, {Id: 5, FirstName: "Tony", LastName: "Ocka", EmailAddress: "toni@oz.com"} ] let result = arr2.filter(d => arr1.includes(d.Id)) console.log(result) 

Answer 2

Also you can do this by iterating through the second array

 let arr1 = [1,2,3]; let arr2 = [ {Id: 1, FirstName: "Bob", LastName: "Jones", EmailAddress: "bob@bob.com"}, {Id: 2, FirstName: "Tessa", LastName: "Wong", EmailAddress: "tes@wong.com"}, {Id: 3, FirstName: "Craig", LastName: "Murray", EmailAddress: "Craig@muz.com"}, {Id: 4, FirstName: "Bryce", LastName: "Willamson", EmailAddress: "email@me.com"}, {Id: 5, FirstName: "Tony", LastName: "Ocka", EmailAddress: "toni@oz.com"} ] let result = []; for(let i in arr2) { if(arr1.indexOf(arr2[i].Id)!==-1) result.push(arr2[i]); } console.log(result); 

Answer 3

You can use a Set to optimize your performance. The lookup operation of an array takes O(n) which increases the overall time complexity of your function to O(n^2) whereas lookup operation in Set takes O(1) so overall time complexity is O(n).

 let arr1 = [1,2,3] let set = new Set(arr1); let arr2 = [ {Id: 1, FirstName: "Bob", LastName: "Jones", EmailAddress: "bob@bob.com"}, {Id: 2, FirstName: "Tessa", LastName: "Wong", EmailAddress: "tes@wong.com"}, {Id: 3, FirstName: "Craig", LastName: "Murray", EmailAddress: "Craig@muz.com"}, {Id: 4, FirstName: "Bryce", LastName: "Willamson", EmailAddress: "email@me.com"}, {Id: 5, FirstName: "Tony", LastName: "Ocka", EmailAddress: "toni@oz.com"}]; let result = arr2.filter(({Id}) => set.has(Id)) console.log(result)