strings only set example

set.js

// ECMA 5
var duplicates = ['taco', 'taco', 'bacon', 'pancake', 'cake', 'salt', 'cake']

var set = {}
duplicates.forEach(function(value) {
  set[value] = true
})

console.log(Object.keys(set)) // Outputs an array with no duplicates

// Check for prescence of a value
console.log('waffles' in set) // false

// Remove value from set
console.log('taco' in set) // true
delete set.taco
console.log('taco' in set) // false

// Iterate over set
Object.keys(set).forEach(function(value) {
  // Do stuff
})