How to test to determine if browser supports JS regex lookahead/lookbehind?

Question

I have a string.replace() function that uses a regex lookbehind.

myString.replace(/(?<!\\)'/gi, '"')

However I see that this feature has limited browser support at this time. https://caniuse.com/#feat=js-regexp-lookbehind

Is there a means to use javascript to test a user's browser's support for this feature?

Something like the CSS.supports() function?

You should write the regex once to achieve the largest compatibility possible. What's the benefit of knowing whether the browser supports lookbehinds? Do you plan on creating multiple regexes? If so then odds are high that your alternate regex is cross-compatible anyways so why hang on to the lookbehind? It just creates a maintenance headache. — MonkeyZeus, Feb 20 '20 at 17:44
Fair enough. This question was more about satisfying my curiosity about how someone might manage the integration of new ES features, rather than finding a solution for a particular production app. — WillD, Feb 20 '20 at 18:11

score 5 · Answer 1 · answered Jan 26 '21 at 05:56

This will return true on chrome and false on safari, without any SyntaxError:

function supportsRegexLookAheadLookBehind() {
  try {
    return (
      "hibyehihi"
        .replace(new RegExp("(?<=hi)hi", "g"), "hello")
        .replace(new RegExp("hi(?!bye)", "g"), "hey") === "hibyeheyhello"
    );
  } catch (error) {
    return false;
  }
}

How to test to determine if browser supports JS regex lookahead/lookbehind?

1 Answers1