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javascript, JAVASCRIPT, DOUBTS - Coggle Diagram

- - - - CAN BE SPARSE
        
        MEANS YOU CAN SET AN VALUE AT ANY INDEX IRRESPECTIVE THAT VALUES FOR INDICES IN BETWEEN HAVE BEEN DEFINED OR NOT
      - MORE LIKE THE LISTS IN PYTHON DIFFERENT TYPES ALLOWED
      - ARRAYS ARE OBJECTS WITH PROPERTIES INDICES LIKE 0 , 1 ,2...
  - - - cannot be changed after declaration
        
        DOUBT does it mean we cannot assign it a new value ANSWER NO
        
        but we could do it in case of undefined
        
        BASCIALLY THEY DONT HAVE ANY IDENTITY
        
        MEANS THE VARIABLE NAME POINTS TO THE VALUE NOT TO THE MEMORY LOCATION WHERE THE VALUE IS LOCATED
        
        doubt between memory location value
    - - Undefined
        
        automatically assign to a variable when we havent assigned value for that variable BUT WE HAVE DEFINED THE VARIABLE
        
        cleared(doubt)
        
        DECALARE A VARIABLE BUT NOT ASSIGN ANY VALUE
        
        it means that space has been allocated for that put no value has been put into it
        
        NOTE that it is different from not defined error which is when variable not declared
      - boolean
        
        true or false
        
        but some other things are also considered as true and false apart from these reserved words
      - null
        
        absense of a value
        
        DOUBTS
        
        where will we use a null type
      - Number
        
        double precession (what it mean s) FLOATING POINT
        
        IEEE STANDARD FOR 64BIT NUMBER
        
        NO INTS
      - SYMBOL
      - STRING
  - - - === compares only if same type
      - == may do type coercion and give weird results
- - - - global
      - function
        
        inside that function in which they are defined
        
        variable scope depend where its function is defined not where the function is invoked
        
        note that its not the nearest declaration to the invocation of function
  - - - use var name_function = function () {}
      - function name_function () {}
      - with parenthesis () we define arguments
        
        but all arguments are optional means even if you defined the function to take three arguments but while invoking you based no argument that is also fine
        
        WHICH ALSO MEANS YOU COULD PASS MORE ARGUEMNTS THEN REQUIRED
- - - - create a new execution context where things will be executed
        
        gets an outer reference from where the function which is being invoked was defined
      - a new variable environment
        
        where variablles and fucntion which are defined within
    - - has a this object