JavaScript Journey — Hour #1

Nayana
1 min readApr 10, 2018

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  • JavaScript has typed values, not typed variables. In other programming languages, variables depicts the type of value stored in the variable, whereas JavaScript is a loosely typed language.
  • JavaScript provides a built-in operator to check/ examine the value stored in the variable. This operator is termed as “typeof” operator.
  • typeof operator always returns a String value.
  • The returned string value of the typeof operator will always be one of the seven data types: string, boolean, number, undefined, object, symbol, function.
  • Trick to Remember: typeof operator returns “object” , if the variable contains either array or null value.
  • Examples:

var checkValue;

console.log(typeof checkValue); // “undefined”

checkValue = 22;

console.log(typeof checkValue); //”number”

checkValue = true;

console.log(typeof checkValue); //”boolean”

checkValue = “JavaScript”;

console.log(typeof checkValue); //”string”

checkValue = undefined;

console.log(typeof checkValue); //”undefined”

checkValue = { language: ‘JavaScript’};

console.log(typeof checkValue); //”object”

checkValue = Symbol(‘happy’);

console.log(typeof checkValue); //”symbol”

checkValue =[1,2,3,4];

console.log(typeof checkValue); //”object”

checkValue = null;

console.log(typeof checkValue); //”object”

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