ReferenceError constructor JS Home  <<  JS Reference  <<  ReferenceError

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In JavaScript you create a ReferenceError instance using the constructor ReferenceError.

Description

Creates a ReferenceError object when trying to dereference a non-existant variable.

Syntax

Parameters

Class Properties

Instance Properties

Class Methods

None.

Instance Methods

None.

Examples

Let's look at some examples of throwing a reference error within our code.

// Throw an error.
try {
  throw new ReferenceError();
} catch (e) {
    alert('A reference error: ' + e.name);
}  

// Throw an error with a message.
try {
  throw new ReferenceError('Throwing a reference error.');
} catch (e) {
    alert('A reference error with message: ' + e.name + ': ' + e.message);
}  

We can also create our own ReferenceError instances as the example below shows.

// Create our own ReferenceError object.
function ourReferenceError(message) {  
  this.name = 'OurReferenceError';  
  this.message = message || 'Default Message Used When No Message Passed';
}   

// Inherit from the ReferenceError prototype.
ourReferenceError.prototype = new ReferenceError();  
ourReferenceError.prototype.constructor = ourReferenceError;   

// Throw an error.
try {  
  throw new ourReferenceError();  
} catch (e) {  
  alert('Our Error: ' + e.name + ' Message: ' + e.message);
}   

// Throw an error and a message.
try {  
  throw new ourReferenceError('A Message we have passed');  
} catch (e) {  
  alert('Our Error: ' + e.name + ' Our Message: ' + e.message);
} finally {  
  alert('A finally statement will always be executed!');
}   

Related Tutorials

JavaScript Advanced Tutorials - Lesson 2 - Errors

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