5-set.js

// start the node repl in the command line:
// $ node --harmony 5-set.js

// Check what functions are available for Set in node --harmony repl
// Object.getOwnPropertyNames(Set.prototype)

var engines = new Set(); // create new Set

engines.add("Gecko"); // add to Set
engines.add("Trident");
engines.add("Webkit");
engines.add("Hippo");
engines.add("Hippo"); // note that Hippo is added twice

console.log("Browser engines include Gecko? " + engines.has("Gecko"));    // true
console.log("Browser engines include Hippo? " + engines.has("Hippo"));    // true
console.log("Browser engines include Indigo? " + engines.has("Indigo"));   // false

engines.delete("Hippo"); // delete item
console.log("Hippo is deleted. Browser engines include Hippo? " + engines.has("Hippo"));    // false