Object Literal Conditional Properties

I’m constantly coming up against adding conditional properties to an Object, in an elegant fashion, but always have to end up doing:

var a = {};
if (someCondition) {
    a.b = 5;
}

I’m sorry but this bothers me!

With the enhancements ES6 has brought to the good old Object, there must be a better way? Turns out the spread operator is guy.

const a = {
  ...someCondition ? {b: 1} : {}
}

Now if … someCondition = true we get a= {b: 1}

And if … someCondition = false we only get a= {}

We can still improve on this syntactically mind you, by using the logical AND operator …

const a = {
  ...someCondition && {b: 1}
}

That’ll do it. By using short circuit evaluation, {b: 1} will only get spread into a if someCondition evaluates to true . If someCondition is false , someCondition is returned, which being false will not be spread into a at all!