Javascript regex replace inserts extra slashes

Question

I'm trying to clean up a file using JavaScript. The file contains lines of text like this:

a <- b + c / d;

I want to replace all <- with = when there is a string of non-whitespace on either side of the <-, separated by a single space. Pretty easy in theory:

line = "a <- b + c / d"
result = line.replace( /(\S+) <- (\S+)/, /$1 = $2/ )

The above code produces /a = b/ + c / d when run. However, conceptually, it should produce a = b + c / d. How can I use $1-style backreferences without allowing JavaScript the opportunity to insert slashes willy-nilly?

Phylogenesis · Accepted Answer · 2013-07-31 12:49:23Z

3

Use a string for the second parameter:

result = line.replace( /(\S+) <- (\S+)/, "$1 = $2" );.

What is happening is the second parameter is being coerced from a RegExp to a String which adds the slashes in the replacement.

answered Jul 31, 2013 at 12:49

Phylogenesis

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Comments

anubhava · Accepted Answer · 2013-07-31 12:50:14Z

0

2nd parameter of replace is not regex but String.

You need to use it like this:

result  = line.replace( /(\S+) <- (\S+)/, '$1 = $2' );

answered Jul 31, 2013 at 12:50

anubhava

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