Some basic Underscore.js methods

underscore_basics.js

/*
*  Some basic Underscore.js methods
*/

var numbers = [1, 2, 2, 3, 5, 5, 8];
var moreNumbers = [3, 6, 7, 8, 9];
var people = [
  {name: "Ben", age: 22},
  {name: "Jim", age: 34},
  {name: "Sally", age: 16}
];

console.log(people);

// Iteration
console.log("*** _.each() ***");
_.each(people, function(person) {
  console.log(person.name);
});

// Selection
console.log("(*** _.select() ***");
var over20 = _.select(people, function(person) {
  return person.age > 20;
});
console.log(over20.length);

// Get properties
console.log("*** _.pluck() ***");
var names = _.pluck(people, "name");
console.log(names);

// 1->1 Operation
console.log("*** _.map() ***");
names = _.map(people, function(person) {
  return "Name: "+person.name;
});
console.log(names);

// N->1 Operation (left)
console.log("*** _.reduce() ***");
names = _.reduce(people, function(memory, person) {
  var append = (memory === "") ? "People: " : memory + ", ";
  return append + person.name;
}, "");
console.log(names);

// N-> Operation (right)
console.log("*** _.reduceRight ***");
names = _.reduceRight(people, function(memory, person) {
  var append = (memory === "") ? "People: " : memory + ", ";
  return append + person.name;
}, "");
console.log(names);

// De-dupliation
console.log("*** _.uniq() ***");
var unique = _.uniq(numbers);
console.log(unique);

// Intersection
console.log("*** _.intersection() ***");
var intersect = _.intersection(numbers, moreNumbers);
console.log(intersect);

// Contains
console.log("*** _.contains() ***");
var contains = _.contains(numbers, 3);
console.log(contains);

// Range
console.log("*** _.range() ***");
var range = _.range(7);
console.log(range);

// Frist
console.log("*** _.first() ***");
var first = _.first(numbers, 3);
console.log(first);

// Last
console.log("*** _.last() ***");
var last = _.last(numbers, 3);
console.log(last);

// Rest
console.log("*** _.rest() ***");
var rest = _.rest(numbers, 3);
console.log(rest);

// Keys
console.log("*** _.keys() ***");
var keys = _.keys(people[0]);
console.log(keys);

// Values
console.log("*** _.values() ***");
var values = _.values(people[0]);
console.log(values);