TypeError

The TypeError object represents an error when an operation could not be performed, typically (but not exclusively) when a value is not of the expected type.

A TypeError may be thrown when:

• an operand or argument passed to a function is incompatible with the type expected by that operator or function; or 
• when attempting to modify a value that cannot be changed; or
• when attempting to use a value in an inappropriate way.

Constructor

TypeError()

Creates a new TypeError object.

Instance properties

TypeError.prototype.message

Error message. Although ECMA-262 specifies that TypeError should provide its own message property, in SpiderMonkey, it inherits Error.prototype.message.

TypeError.prototype.name

Error name. Inherited from Error.

TypeError.prototype.fileName

Path to file that raised this error. Inherited from Error.

TypeError.prototype.lineNumber

Line number in file that raised this error. Inherited from Error.

TypeError.prototype.columnNumber

Column number in line that raised this error. Inherited from Error.

TypeError.prototype.stack

Stack trace. Inherited from Error.

Examples

Catching a TypeError

try {
  null.f() 
} catch (e) {
  console.log(e instanceof TypeError)  // true
  console.log(e.message)               // "null has no properties"
  console.log(e.name)                  // "TypeError"
  console.log(e.fileName)              // "Scratchpad/1"
  console.log(e.lineNumber)            // 2
  console.log(e.columnNumber)          // 2
  console.log(e.stack)                 // "@Scratchpad/2:2:3\n"
}

Creating a TypeError

try {
  throw new TypeError('Hello', "someFile.js", 10) 
} catch (e) {
  console.log(e instanceof TypeError)  // true
  console.log(e.message)               // "Hello"
  console.log(e.name)                  // "TypeError"
  console.log(e.fileName)              // "someFile.js"
  console.log(e.lineNumber)            // 10
  console.log(e.columnNumber)          // 0
  console.log(e.stack)                 // "@Scratchpad/2:2:9\n"
}

Specifications

Browser compatibility

See also

• Error