Type.md

Types, Values, and Variables Back

• JavaScript's types can be divided into primitive types and object types.
• JavaScript's types can also be categorized as mutable and immutable types.
  • mutable types: value can change
    • Objects
    • Arrays
    • ...
  • immutable types: value can not change
    • Numbers
    • booleans
    • null
    • undefined
    • strings
    • symbol (new in ES6)
    • ...

var x;
x = 0;
x	//=>0

//JavaScript supports several types of values
x = 1;	//integers
x = 0.1;	//real
x = "Aloha";	//String in quatation marks
x = 'Aloha';	//String in single quatations 
x = true;	//boolean
x = null;	//no value
x = undefined;	//like null

• Arithmetic
• Infinity & NaN
• Precision
• Date and Times
• Text
• Wrapper Object(包裝對象)