正则表达式替换字符串中不在引号中的单词

Question

I'm looking to do replacements in unknown third-party inputs in strings that sometimes have quotes among them.

I want to replace a wholeword whereever it occurs unless it's in double or single-quotes, and unless the quote is escaped.

Example: Replacing FOO by BAR

Input:

FOO "FOO" 'FOO' "    1 + FOO + 2 " ABCFOOXYZ "  str1\"FOO\"str3'FOO'\'\'" '  str1\'FOOstr3"FOO"\"\"' \"FOO\"

Expected output:

BAR "FOO" 'FOO' "    1 + FOO + 2 " ABCFOOXYZ "  str1\"FOO\"str3'FOO'\'\'" '  str1\'FOOstr3"FOO"\"\"' \"BAR\"

More tests:

name: FOO
favoriteQuote: "I am my own FOO."
children: 'FOO\'s children'
cars: ownersList[FOO]
statement = FOO + " is the owner of the house."

Expected output:

name: BAR
favoriteQuote: "I am my own FOO."
children: 'FOO\'s children'
cars: ownersList[BAR]
statement = BAR + " is the owner of the house."

I saw this question: Match and replace a word not in quotes (string contains escaped quotes) which I thought was similar and could be a good starting point the accepted answer does not work at all:

https://regex101.com/r/Lfan64/5

If anyone could help me get the expected result from my regex that would be great, thanks.

Answer 1

If I am understanding your requirements correctly, you may try this regex for your cases:

((['"])(?:\\.|(?!\2).)*(?<!\\)\2)|\bFOO\b/g

Updated RegEx Demo

This regex uses alternation to match and discard what we need to keep on LHS of | whereas on RHS we match whatever we want to replace in the result.

Code:

 const str = String.raw`name: FOO favoriteQuote: "I am my own FOO." children: 'FOO\'s children' cars: ownersList[FOO] statement = FOO + " is the owner of the house." FOO "FOO" 'FOO' " 1 + FOO + 2 " ABCFOOXYZ " str1\"FOO\"str3'FOO'\'\'" ' str1\'FOOstr3"FOO"\"\"' \"FOO\"`; var repl = str.replace(/((['"])(?:\\.|(?.\2)?)*(,<,\\)\2)|\bFOO\b/g; (_. g) => g || "BAR"); console.log(repl);

RegEx Details:

• ( : Start capture group #1
  • (['"]) : Match ' or " in capture group #2
  • (?:\\.|(?.\2).)* : Match an escaped character or any character except the quote we matched in capture group #2
  • (?<!\\)\2 : Match whatever quote we matched in capture group #2 as long as it is not preceded by a \
• ) : End capture group #1
• | : OR
• \bFOO\b : Match complete word FOO

Answer 2

You can use

 const text = String.raw`name: FOO favoriteQuote: "I am my own FOO." children: 'FOO\'s children' cars: ownersList[FOO] statement = FOO + " is the owner of the house." FOO "FOO" 'FOO' " 1 + FOO + 2 " ABCFOOXYZ " str1\"FOO\"str3'FOO'\'\'" ' str1\'FOOstr3"FOO"\"\"' \"FOO\"` console.log( text.replace( /((?:[^\\]|^)(?:\\{2})*(?:"[^"\\]*(?:\\[^][^"\\]*)*"|'[^'\\]*(?:\\[^][^'\\]*)*'))|FOO/g, (match, group) => group || "BAR" ))

Details :

• ((?:[^\\]|^)(?:\\{2})*(?:"[^"\\]*(?:\\[^][^"\\]*)*"|'[^'\\]*(?:\\[^][^'\\]*)*')) - Group 1:
  • (?:[^\\]|^) - a char other than \ or start of string
  • (?:\\{2})* - zero or more sequences of double backslash
  • (?:"[^"\\]*(?:\\[^][^"\\]*)*"|'[^'\\]*(?:\\[^][^'\\]*)*') - either of a double or single quoted string literal pattern with escape sequence support
• | - or
• FOO - a FOO string in any other context.

The (match, group) => group || "BAR" (match, group) => group || "BAR" replacement means that if Group 1 matches, the replacement is Group 1 value, else, the replacement is BAR .