ECMAScript 6 arrow function that returns an object

When returning an object from an arrow function, it seems that it is necessary to use an extra set of {} and a return keyword because of an ambiguity in the grammar.

That means I can’t write p => {foo: "bar"}, but have to write p => { return {foo: "bar"}; }.

If the arrow function returns anything other than an object, the {} and return are unnecessary, e.g.: p => "foo".

p => {foo: "bar"} returns undefined.

A modified p => {"foo": "bar"} throws “SyntaxError: unexpected token: ':'”.

Is there something obvious I am missing?

You must wrap the returning object literal into parentheses. Otherwise curly braces will be considered to denote the function’s body. The following works:

p => ({ foo: 'bar' })

You don't need to wrap any other expression into parentheses:

p => 10
p => 'foo'
p => true
p => [1,2,3]
p => null
p => /^foo$/

and so on.

Reference: MDN - Returning object literals

Stack Overflow Q#28770415, score: 1470