error in js code example

Example 1: javascript try

var someNumber = 1;
try {
  someNumber.replace("-",""); //You can't replace a int
} catch(err) {
 console.log(err);
}

Example 2: 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 3: 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 4: javascript throw new error

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

Example 5: JavaScript Errors

<p id="demo"></p>

<script>
try {
  adddlert("Welcome guest!");
}
catch(err) {
  document.getElementById("demo").innerHTML = err.message;
}
</script>

Example 6: javascript string error

Error.prototype.toString = function() {
  'use strict';

  var obj = Object(this);
  if (obj !== this) {
    throw new TypeError();
  }

  var name = this.name;
  name = (name === undefined) ? 'Error' : String(name);

  var msg = this.message;
  msg = (msg === undefined) ? '' : String(msg);

  if (name === '') {
    return msg;
  }
  if (msg === '') {
    return name;
  }

  return name + ': ' + msg;
};