• Every function in JavaScript is a **Function **object.
• To return a value other than the default, a function must have a **return **statement. A function without a return statement will return a default value.
• The parameters of a function call are the function's arguments. Arguments are passed to functions by value.

const getRectArea = function(width, height) { return width * height; };}

• function name, which can be omitted in function expressions to create anonymous functions
• Function expressions in JavaScript are not hoisted,
• If you want to refer to the current function inside the function body, you need to create a named function expression. This name is then local only to the function body (scope)
• The variable the function expression is assigned to will have a name property. The name doesn't change if it's assigned to a different variable. If function name is omitted, it will be the variable name (implicit name). If function name is present, it will be the function name (explicit name)

• Does not have its own bindings to this or super, and should not be used as methods.
• Does not have arguments, or new.target keywords.
• Not suitable for call, apply and bind methods, which generally rely on establishing a scope. *Can not be used as constructors.
• Can not use yield, within its body.

function calcRectArea(width, height) { return width * height; }

It is a function that can be stoped in the middle and after some event it can go back and pickup from the place it stopped.

Traditional Function function (a){ return a + 100; }

Arrow Function Break Down

1. Remove the word "function" and place arrow between the argument and opening body bracket (a) => { return a + 100; }

2. Remove the body brackets and word "return" -- the return is implied. (a) => a + 100;

3. Remove the argument parentheses a => a + 100;

1. dfference between function expression and decalrartion:

• name - Function expresion doesnt need name (it will be anonymous function)
• hoisting - F.expr are not hoisted unlike F.declar.

2. what is anonymuous function.
3. Difference between method and function.

• Function can be called by its name, method is property of object:

function functionName(parameters) { // Content }

object = { methodName: function() { // Content } };object.methodName()

4. When to use each function