Use do { } makes React render() method more readable

do notation.js

// FP languages permit to evaluate if/else expressions as values.
// In many cases it permits to avoid using mutable variables (var/let), multiple returns, or nested ternary operators

// This is the do { } notation (stage 0), that permits to write the following right now with Babel.

const Users = ({users}) =>   (
  <div>
    {users.map(user =>
      <UserCard key={user.id} user={user}/>
    )}
  </div>
)  

const UserList = ({users}) => do {
  if (!users) <div>Loading</div>
  else if (!users.length) <div>Empty</div>
  else <Users users={users}/>
}

@gre I agree with you and often use code-blocks in scala to limit the scope of unnecessary variables.

I'm not sure it can work with switch because in switch it's not like pattern matching, and you can enter on multiple "branches" if you don't use break/return. Inside do {}, if you don't use return on switch it... does not return anything. If you put a return it says you are not in a function context so can't return.

I guess what you want is this in a more idiomatic way? I'd also love that

const CodeBlockResult = (() => {
  const someEnum = "case1";
  switch (someEnum) {
    case "case1": return "val1";
    case "case2": return "val2"
    case "case3": return "val3"
    default: return "val4"
  }
})();

Isn't it annoying to have to use let reassignment with switch, or this weird function syntax ? :)

can't wait pattern matching :D