Error object to string

Question

I want to use regular expression for error message...

try {
  throw new Error("Foo 'bar'");
} catch (err) {
  console.log(getInQuotes(err));
}

... where getInQuotes is a function for string:

var getInQuotes = function(str) {
  var re;
  re = /'([^']+)'/g;
  return str.match(re);
};

... but got error:

Object Error: Foo 'bar' has no method 'match'

Although it works for usual string:

console.log(getInQuotes("Hello 'world'"));

result:

[ '\'world\'' ]

Tried to stringify Error object ...

console.log("stringify: " + JSON.stringify(err));

... but it's empty:

stringify: {}

C3roe · Accepted Answer · 2013-06-28 11:50:01Z

5

You created an Error object, and that's not a string. But you can simply solve this by calling its toString method, and applying match on the result of that:

function getInQuotes(err) {
  var re;
  re = /'([^']+)'/g;
  return err.toString().match(re);
};

answered Jun 28, 2013 at 11:50

C3roe

97.8k15 gold badges100 silver badges172 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Anand · Accepted Answer · 2013-06-28 11:53:42Z

1

Just try this http://jsfiddle.net/B6gMS/1/

getInQuotes(err.message)

answered Jun 28, 2013 at 11:53

Anand

15k8 gold badges35 silver badges44 bronze badges

Comments

Venkat.R · Accepted Answer · 2021-06-20 09:13:26Z

Basically, here we are trying to get the annotated string. if we go with Regular Expression then we need a right case if there is a real need for this.

if not, below string replace would be easier solution.

// Arrow Function read given string and strip quoted values.
// Basic example
const getInQuotes = (str) => str.replace( /^[^']*'|'.*/g, '' );

In order to keep it more generic. below function helps to keep this annotator (') can be configurable. below code is in latest ES2021 code.

This uses template literals in RegExp Function.
Annotator is configurable
change the method name getInQuotes to getAnnotatedStrings which is meaningful.
method return always array in order to keep it predictable and avoid other errors.
Its good not to pass entire object since its requires only the error message.

function getAnnotatedStrings(errorMessage, annotator = "'") {
  if (!annotator || !errorMessage) return []

  const regex = new RegExp(`${annotator}([^']+)${annotator}`, 'g')
  return errorMessage.toString().match(regex);
}

Actual in ES2021 Code.

try {
  throw new Error("Foo 'bar'");
} catch (e) {
  console.log(getAnnotatedStrings(e?.message)); // outputs - bar
}

Refer: Error Object Intro
Regex Functions and Basics
Template Literals

Ander2 · Accepted Answer · 2013-06-28 11:51:01Z

0

err is not a string it's an Error object, so it has no .match() function . You Should call the function using Error object's toString() method, just this way:

try {
    throw new Error("Foo 'bar'");
} 
catch (err) {
    console.log(getInQuotes(err.toString())); 
}

answered Jun 28, 2013 at 11:51

Ander2

5,6682 gold badges25 silver badges45 bronze badges

Collectives™ on Stack Overflow

Error object to string

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related