fake-js-switch-expression.js

/**
 * Ruby has these nice case expressions, but switches are statements in JS.
 * Here's a little convention to make switch statements look a little more like expressions.
 * 
 * This uses ES6, but of course you could do it with ES5 as well. This pattern is especially
 * nice in ES6, however, especially when you want to use const instead of let or var.
 */

const output = (() => {
  switch(input) {
    case 1: return 'one';
    case 2: return 'two';
    case 3: return 'three';
    default: return 'default';
  }
})();

switch-expression.rb

# For comparison, the Ruby might look like:

output = case input
when 1
  "one"
when 2
  "two"
when 3
  "three"
else
  "default"
end