Type conversions like JavaScript

JavaScript is an untyped language, but at the same time JavaScript provides a flexible way to handle automatic type conversions. The basic rule is that if a value of a type is used in an environment that requires other types of values, JavaScript automatically converts that value to the desired type.

The following is the conversion that is performed when a specific type of JavaScript is used in a particular environment.

Type conversions

Value String Numeric Boolean object

"Undefined" NaN false Error not defined

Null "NULL" 0 false Error

Non-empty string as is the numeric value of the string or the Nan True string object

Empty string as is 0 false string object

0 "0" as is false number object

Nan "Nan" as is false number object

Infinity "Infinity" as is true Number object

Negative Infinity "-infinity" as is true Number object

String value of all other numeric numbers Asis true Number object

True "true" 1 as is Boolean object

False "false" 0 as is Boolean object

Object ToString () valueOf () or ToString () or Nan true as is

Type conversions like JavaScript