1. JavaScript Yoav Rubin, [email_address] 24.06.10

6. JavaScript type system

14. I’ll have what she’s having – prototypal inheritance

17. The prototype (pType) The object (theObject) theObject.age; // 32 pType.age ++; The object (theObject) The prototype (pType) theObject.age; // 33 delete theObject.age; // nothing happens theObject.age; // 33 delete pType.age; // no more age field theObject.age; // undefined “ Mr” title: “ barber” job: 32 age: “ Jeff” name: “ Mr” title: “ barber” job: 33 age: “ Jeff” name:

18. The prototype (pType) The object (theObject) theObject.age; // 32 theObject.age ++; // value read from pType, added to theObject The object (theObject) The prototype (pType) theObject.age; // 33 delete theObject.age; // no more age member in theObject theObject.age; // 32 delete pType.age; theObject.age; // undefined “ Mr” title: “ barber” job: 32 age: “ Jeff” name: “ Mr” title: “ barber” job: 32 age: “ Jeff” name: 33 age:

20. (From the tyranny of the compiler)

21. Functions

25. Write a function that calculates the fibonacci value of a number

39. function Counter(){ var count = 0; this.getValue = function(){ return count ;}; this.increase = function(){count ++;}; this.decrease = function(){count --;}; this.setValue = function(newVal){count = newVal;}; } var c = new Counter(); c.setValue(5); c.increase(); c.getValue(); // 6 c. count; // undefined public public public public private

41. Write a function that receives an array of objects and sets their showIndex method to show their index in that array

44. “Everything should be made as simple as possible, but not simpler” Albert Einstein

45. What happens when things are too simple (the dark side of JavaScript)

50. with(obj){ a = b } if(obj.a === undefined){ if(obj.b === undefined){ a=b ;// two global variables } else { a = obj.b; // a is global, b is not } else { if(obj.b === undefined){ obj.a=b; // b is global , a not } else { obj.a = obj.b; // both not global } } The ‘with’ keyword obj.a = obj.b; // both not global obj.a = b; // b is global, a is not + a = obj.b; // a is global, b not a=b; // two global variables - + - a (exist in obj)