js notes

1 files changed, 59 insertions, 1 deletions

diff --git a/jsnotes.txt b/jsnotes.txt
index d28e473..ea4a049 100644
--- a/jsnotes.txt
+++ b/jsnotes.txt
@@ -1,7 +1,27 @@
+JS...
+- JS includes keyval as language construct (aka associative array/hashtable/dictionary),
+  this brings confusion and multiple ways to do 1 thing (as objects, arrays, and functions can be interchangeable)
+- everything is an object, if that wasn't enough, JS is reflective,
+  at any point we may add/mutate properties of object e.g. foo.newmember = "bar";
+
+Best practices / rule of thumb
+- when in doubt how to store data, always start with JSON (don't sore functions)
+- always use 'var' keyword unless you're dereferencing a global
+
+Functions
+- all functions are objects
+- 'this' keyword can be used in function if it is being new'ed (as in creating object/instance),
+  if function was called without 'new' then this.foo will bind to window.foo ...
+- NEW keyword, JS expects a constructor when new'ing, this implies we should NEW a function,
+  new'ing e.g. 'new {} throws TypeError: object is not a function'
+
+
 [references]
 http://msdn.microsoft.com/en-us/library/ie/d1et7k7c%28v=vs.94%29.aspx
 
 [data types]
+- built-ins?
+    the keval/dictionary/hash/associate-array language construct
 - primitive
   string, number boolean
 
@@ -15,6 +35,9 @@ http://msdn.microsoft.com/en-us/library/ie/d1et7k7c%28v=vs.94%29.aspx
   null, undefined
   note: null is not 0, does not have type, undefined is a string
 
+[scope]
+- var keyword is used to make local variables
+
 [anonymous functions]
 wrapping code inside of 'function() { code } ()' is handy for creating a
 namespace for your code and restricting scope, since js essentially has
@@ -38,4 +61,39 @@ defined in
   when function is assigned to this object, only 1 copy exists, it is memory
   efficient, also we get expected behavior when overriding that function
 - 'new' changes meaning of a function, upon invocation, function is ran in blank
-  object context
\ No newline at end of file
+  object context
+
+
+[some examples]
+> 4 - 2    is 2
+> 4 - "2"  is 2
+> "4" + 2  is "42"
+
+> 0 == false  true
+> 1 == "1"    true  (js
+> 1 === "1"   false (no type coercion is taking place)
+
+> [] + []     "" empty string
+> [] + {}     {object Object] Object
+> {} + []     0
+> {} + {}     NaN
+
+
+~~~~~----- BROWSER -----~~~~~
+
+[JS in a browser]
+- there are 3 main global objects
+  1) window......is the execution context and global object for that context's JS
+  2) document....contains the HTML
+  3) screen......describes the physical display's full screen
+
+
+- your code gets executed inside something that looks like
+
+    with (window) {
+        //Your code
+    }
+
+- console.log is not available in to use from within HTML->JS, however it does exist in browser's console (Ctrl+Shift+k or F12)
+
+~~~~~----------~~~~~