Errors
Published Jul 23, 2021Updated Sep 9, 2021
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When JavaScript throws an error it throws an error object that consists of a name
and a message
property. The name
is the general type of the error, and the message
is a human-readable description of the specific error that happened.
Thrown errors are caught by the next outer catch
block of a try...catch...finally
statement. They can also be thrown intentionally by the throw
statement.
The Error Object
The error object holds information about the exception that was thrown in its two properties:
name
Sets or returns an error name. (Type of Error)message
Sets or returns an error message. (Description of specific instance.)
The following types of error can be returned by the name
property:
- “EvalError” An error has occurred in the eval() function (Note: Depreciated in newer versions of JavaScript)
- “RangeError” A number “out of range” has occurred
- “ReferenceError” An illegal reference has occurred
- “SyntaxError” A syntax error has occurred
- “TypeError” A type error has occurred
- “URIError” An error in encodeURI() has occurred
These are some example messages for various types of errors:
- RangeError
- invalid array length
- invalid date
- ReferenceError
- “x” is not defined
- assignment to undeclared variable “x”
- SyntaxError
- “x” is a reserved identifier
- a declaration in the head of a for-of loop can’t have an initializer
- TypeError
- “x” is not a function
- “x” is read-only
- URIError
- malformed URI sequence
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