js error class code example

Example 1: javascript throw new error

throw new Error("Error message here"); // Uncaught Error: Error message here

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
}