How does this object method definition work without the “function” keyword?

Question

I discovered this by accidentally leaving off the function keyword. Ordinarily the foobar method in the module below would be declared as fo

Answer 1

ES6 allows "concise methods" which, as you've discovered, aren't cross-browser compatible yet.

Answer 2

How is it possible that this runs at all in any browser? Is is some sort of new ES6 functionality?

Yes.

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Method definitions

A property of an object can also refer to a function or a getter or setter method.

var o = {
  property: function ([parameters]) {},
  get property() {},
  set property(value) {},
};

In ECMAScript 6, a shorthand notation is available, so that the keyword "function" is no longer necessary.

// Shorthand method names (ES6)
var o = {
  property([parameters]) {},
  get property() {},
  set property(value) {},
  * generator() {}
};

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