Functions

Question 1

Ways to create functions

Answer 1

5 Ways

1. Function Declarations
2. Function Expressions
3. Function Constructor
4. Fat Array Functions
5. Method Definitions

Question 2

Function Declarations

Answer 2

• functions are statements
• cannot be anonymous
• are hoisted
• can reference function inside (and outside) body using function name

Question 3

Function Expressions

Answer 3

• var func = function() { }
• is not hoisted
• if named, can reference function inside body (but not outside) using function name

Question 4

Function constructor

Answer 4

• the native Function constructor can be used to create function
• functions created with constructor do not have access to closure
• this approach is strongly discouraged

Syntax

• var myFunct = new Function(‘arg1’, ‘arg2,’ ‘body’);
  • The first n-args becomes the names of the params of the new function
  • And the ‘body’ string becomes the body of the function

Question 5

Fat Arrow Functions

Answer 5

• shorter syntax for making functions
• must be anonymous
• this ​binding is determined by value of this in enclosing execution context, NOT by invoking function
• cannot be used as a constructor
• do not have access to an arguments variable

Syntax

• (x, y) => {

x = x + y;

return x;

}

// If function only has 1 statement, we can remove brackets and return keyword

(x, y) => x

// If function only has 1 argument, we can remove the parens

y => x

Question 6

Method Definitions

Answer 6

• a shorter way of writing methods
• created as methods in objects or in classes
• cannot be used as constructors
• var obj = {

myFunc: function( ) { },

myFunc2( ) { }

}