Use the result of one regular expression in another - javascript

Question

I am trying to retrieve some pieces of data from a URL using regular expressions in Javascript.

const url = "/node_modules/@company/dl-atoms-control/README.md";

The following RegEx retrieves text preceded by the string "dl-" In this case "atoms":

const molecularTypePlural = url.match(/(?<=dl-)\w+/gm)[0];

I now want to use molecularTypePlural in a second RegEx to retrieve the string preceded by "dl-atoms-" which in this case is "control". I can't hard code this because the molecularTypePlural variable will have different values with different URLs. I have tried the below:

const packageNameRegex = new RegExp(`/(?<=dl-${molecularTypePlural}-)\w+/gm`);
const packageName = nodePath.match(packageNameRegex);

However the RegEx doesn't return any results. Logging packageNameRegex reveals that the RegEx seems to be incorrectly formatted:

"/\/(?<=dl-atoms-)w+\/gm/"

I think it might be a problem with escaping special characters but I'm not 100% sure. Could anyone show me where I'm going wrong. Thanks

I did see this answer but I don't really understand the example given tbh. — James Howell, Nov 02 '18 at 14:46
I think the problem is in how you constructing regex. You use`new Regex(...)` and inside you put string which contains regular expression literal. — qwermike, Nov 02 '18 at 15:00
I think smth like this: `new RegExp(\`(?<=dl-${molecularTypePlural}-)\\w+\`, 'gm')` — qwermike, Nov 02 '18 at 15:08
I think I'm nearly there with this: const packageNameRegex = new RegExp(`$\?<\=dl-${molecularTypePlural}-$\\w\+`, 'gm'); That returns an array of one item with the string I'm after. Thanks very much for your help — James Howell, Nov 02 '18 at 15:12

Use the result of one regular expression in another - javascript

0 Answers0