Escaping double quotes in JavaScript from a string in a variable

Question

I have these two scenarios:

console.log(('hello "friend" what\'s up?').replace(/\"/g, '\\"'));

I receive the expected result:

hello "friend" what's up?

But, if I do this:

var val = 'hello "friend" what\'s up?';
val.replace(/\"/g, '\\"');
console.log(val);

I get...

hello "friend" what's up?

(the result needs to be hello \"friend\" what's up?)

The only difference is that the second one uses an already created variable that contains the string. Why doesn't the second scenario actually replace the double quotes with \"?

Possible duplicate: Escaping double quotes in JavaScript

Peter Mortensen
– Peter Mortensen

2020-07-19 18:08:25 +00:00
Commented Jul 19, 2020 at 18:08 — Peter Mortensen
– Peter Mortensen, Commented Jul 19, 2020 at 18:08

Anthony Grist · Accepted Answer · 2014-12-22 22:06:39Z

3

From the MDN documentation:

The replace() method returns a new string with some or all matches of a pattern replaced by a replacement.

You need to do val = val.replace(/\"/g, '\\"'); so that you're assigning the new string returned by calling replace to your variable.

answered Dec 22, 2014 at 22:06

Anthony Grist

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2 Comments

Andres SK Over a year ago

I feel stupid. Had my "jQuery" mode on, as in $(this).attr('something', 'value'); Thank you!

Peter Mortensen Over a year ago

Is it necessary to use regular expressions for simple substitutions of literal strings?

Peter Mortensen · Accepted Answer · 2020-07-21 18:47:05Z

1

Actually by doing

val.replace(/\"/g, '\\"');

You're not assigning the replaced value back to val. For that you will need:

val = val.replace(/\"/g, '\\"');

edited Jul 21, 2020 at 18:47

Peter Mortensen

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answered Dec 22, 2014 at 22:06

anubhava

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Comments

Mechkov · Accepted Answer · 2014-12-22 22:06:26Z

0

val.replace(/\"/g, '\\"');

In the above code you are not reassigning to val;

Try this to get the expected result.

val = val.replace(/\"/g, '\\"');

answered Dec 22, 2014 at 22:06

Mechkov

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