gistfile1.js

// declaration
function foo (n) { return n + 1; }

// expression
// note, fat arrow functions have very different meaning (usually what I want, though)
var foo = function (n) { return n + 1; };
var foo = (n) => { return n + 1; };
var foo = n => n + 1;

// object methods
var obj = {
  // these are just expressions, but to some beginners they seem different
  foo: function (n) { return n + 1; },
  foo: (n) => { return n + 1; },
  foo: n => n + 1,

  // concise method
  foo () {}
}

class foo {} // <-- actually just a function

class Thing {
  foo () {} // <-- no comma
  bar () {}
}