One liner for push to array only if its not undefined else assign

Question

i wrote the following code .is there any one liner for the following ?

if (this.selectedUsersToAdd.length) {
  this.selectedUsersToAdd.push(selectedUsersToAdd);
} else {
  this.selectedUsersToAdd = selectedUsersToAdd;
}

Nenad Vracar · Accepted Answer · 2018-05-18 16:21:17Z

2

You can use ternary operator and assign value of array you want to add if first one is empty or result of concat if it's not empty.

let arr = [];
let add = [1, 2];
arr = arr.length ? arr.concat(add) : add;

console.log(arr)

In case you want to push whole new array to old one if old one is not empty, then first push new one and return old one.

let arr = [1];
let add = [1, 2];
arr = arr.length ? (arr.push(add), arr) : add;

console.log(arr)

answered May 18, 2018 at 16:21

Nenad Vracar

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Comments

Alex Dovzhanyn · Accepted Answer · 2018-05-18 16:16:58Z

1

Using a ternary:

this.selectedUsersToAdd.length ? this.selectedUsersToAdd.push(selectedUsersToAdd) : this.selectedUsersToAdd = selectedUsersToAdd

answered May 18, 2018 at 16:16

Alex Dovzhanyn

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