Regex Pattern: Match outer single & double quote pairs

Here are a couple regular expressions for matching quote pairs in a string.

This pattern can be quite handy for attempting to fix malformed JSON.

Match outer ' single quotes

Matching all outer single quotes in a given string:

/(?:')(?=(?:[^']|'[^]*')*$)/g

Given this string:

this is my string 'foo bar 'baz lol hi'

The regex will only match 'foo + hi' & ignore the inner quote in 'baz (minus the words of course)

This is quite handy for trying to fix malformed JSON that contains single ' vs the required double "

const matchSingleQuotesRegex = /(?:')(?=(?:[^']|'[^]*')*$)/g

const malformedJSON = `{'lol': 'wh'atevr'}`

const fixedJSON = malformedJSON.replace(matchSingleQuotesRegex, '"')
console.log(fixedJSON)
/* Yay fixed */
// {"lol": "wh'atevr"}

Try it yourself

Match outer " double quotes

Matching all outer double quotes in a given string:

/(?:")(?=(?:[^"]|"[^]*")*$)/g

Given this string:

this is my string "with stuff " in quotes"

The regex will only match "with + quotes" & ignore the inner quote in stuff " in.

Usage in code:

const matchDoubleQuotesRegex = /(?:")(?=(?:[^"]|"[^]*")*$)/g

const original = `
newX {"lol": "whatevr"}
str {"lol": "hey"'there"}
`

const newStringWithSingleQuotes = original.replace(matchDoubleQuotesRegex, "'")
console.log(newStringWithSingleQuotes)
/*
newX {'lol': 'whatevr'}
str {'lol': 'hey"'there'}
*/

Try it yourself