custom errors javascript code example

Example 1: js errors

JS Errors
try
Lets you define a block of code to test for errors
catch
Set up a block of code to execute in case of an error
throw
Create custom error messages instead of the standard JavaScript errors
finally
Lets you execute code, after try and catch, regardless of the result

Example 2: js errors

JS Error Name Values:
name
Sets or returns the error name
message
Sets or returns an error message in string from
EvalError
An error has occurred in the eval() function
RangeError
A number is “out of range”
ReferenceError
An illegal reference has occurred
SyntaxError
A syntax error has occurred
TypeError
A type error has occurred
URIError
An encodeURI() error has occurred

Example 3: js throw custom error

class CustomError extends Error {
  constructor(foo = 'bar', ...params) {
    // Pass remaining arguments (including vendor specific ones) to parent constructor
    super(...params)

    // Maintains proper stack trace for where our error was thrown (only available on V8)
    if (Error.captureStackTrace) {
      Error.captureStackTrace(this, CustomError)
    }

    this.name = 'CustomError'
    // Custom debugging information
    this.foo = foo
    this.date = new Date()
  }
}

try {
  throw new CustomError('baz', 'bazMessage')
} catch(e) {
  console.error(e.name)    //CustomError
  console.error(e.foo)     //baz
  console.error(e.message) //bazMessage
  console.error(e.stack)   //stacktrace
}