Switch statement alternative using object

switch-object.js

var classifyShape = function(shape) {

  var isTriangle = function() {
    console.log('A triangle is a polygon with 3 sides.')
  }

  var isQuadrangle = function() {
    console.log('A quadrangle is a polygon with 4 sides.')
  }

  var isPentagon = function() {
    console.log('A pentagon is a polygon with 5 sides.')
  }

  var isUnknown = function() {
    console.log('Unknown shape.')
  }

  var shapes = {
    'isosceles': isTriangle,
    'rectangle': isQuadrangle,
    'square': isQuadrangle,
    'unknown': isUnknown
  }

  return (shapes[shape] || shapes['unknown'])()

}

classifyShape('square')
classifyShape('isosceles')
classifyShape('qwerty')