JavaScript flattening an array of arrays of objects

Question

I have an array which contains several arrays, each containing several objects, similar to this.

[[object1, object2],[object1],[object1,object2,object3]]
         


        

Answer 1

You can use Array.concat like bellow:-

var arr = [['object1', 'object2'],['object1'],['object1','object2','object3']];
var flattened = [].concat.apply([],arr);

flattened will be your expected array.

ES 2020 gives the flat, also flatMap if you want to iterate over, to flat lists of lists:

[['object1'], ['object2']].flat() // ['object1', 'object2']