Description

Use the throw statement to throw an exception. When you throw an exception, expression specifies the value of the exception. Each of the following throws an exception: 

throw 'Error2'; // generates an exception with a string value
throw 42;       // generates an exception with the value 42
throw true;     // generates an exception with the value true
throw new Error('Required');  // generates an error object with the message of Required

Also note that the throw statement is affected by automatic semicolon insertion (ASI) as no line terminator between the throw keyword and the expression is allowed.