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JavaScript typeof Operator and Type Checking

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Data Types: JavaScript has six primitive types: String, Number, Boolean, null, undefined, Symbol, and Object
Primitive types are basic values like string, number, boolean
Objects are collections of properties in name-value pairs
Special types include arrays, functions, regular expressions, and Date
typeof Operator: typeof evaluates to string indicating type of operand
Can be used with parentheses for function invocation
Prior to ES6, typeof always returned string regardless of operand
Block-scoped variables declared with let/const throw ReferenceError before initialization
Type Checking Limitations: typeof can be misleading for primitive types like null and []
NaN values return "number" type by typeof
Array types return "object" by typeof
Everything in JavaScript is not an object
Better Type Checking: Use instanceof operator for object type checking
Check for NaN using Number.isNaN() or Object.is()
Object.toString() method provides generic type checking
Primitive types can be accessed through implicit wrapper objects