A simple gist to show how to use JavaScript objects and arrays

objects_and_arrays.js

/* 
Objects are containers for named values called properties or methods.
Objects are mutable ie its values can be changed other js variables are immutable
Objects are passed/called by reference not value
eg var obj = {name: "John"};
var x = obj;
x.name = "Mike"; This would also change the value of obj.name to "Mike"
Primitive data types (number, boolean, string) are passed by value
Date, Math, Array, RegExp, etc are all objects
NB: Math does not inherit from Object.prototype because it is a global object
Almost everything in JS is an object(even functions)
*/

// var student = {
//   name: "John"
// }

// console.log(student);
// delete student.name;
// student.age = 22;
// console.log(student);

// var x = new String("Hi");
// // x = "Hi";
// console.log(x);

// function Woman(firstName, lastName) {
//   this.firstName = firstName;
//   this.lastName = lastName;
//   // this.fullName = function() {
//   //   return firstName + " " + lastName;
//   // }
// }

// Woman.prototype.fullName = function() {
//   return this.firstName + " " + this.lastName;
// };

// var woman1 = new Woman("Shade", "Adebayo");

// console.log(woman1.fullName());
// console.log("firstName" in woman1)
// for(var prop in woman1){
//   console.log(prop);
// }

// for(var prop in woman1){
//   if(woman1.hasOwnProperty(prop)) {
//     // hasOwnProperty() checks only props declared
//     // explicitly in the constructor ie excludes
//     // inherited from the prototype
//     console.log(prop);
//   }
// }

// var x = Math.PI;            // Returns PI
// var y = Math.sqrt(16);      // Returns square root

// console.log(x, y);

// var nums = [2, 4, 6, 8, 10];
// var total = 0;
// for(var i = 0; i < nums.length; i++) {
//   // if(nums[i] === 6) continue;
//   // console.log(nums[i]);
//   total += nums[i];
// }
// console.log(total);
// console.log(nums[2]);

// var ages = new Array(3);
// ages[0] = 23;
// ages[1] = 19;
// ages[2] = 33;
// ages[3] = 25;
// ages[4] = 17;
// console.log(ages[0])

// ages.push(12);
// ages.pop();

// ages.shift();
// ages.unshift(10, 24);
// splice() is used to remove and add elements
// var filteredAges = ages.slice(1, 3);
// console.log(filteredAges);
// console.log(ages);