testing if a string matches a regEx combined with a variable containing slashes

Question

I have an array containing strings such as

/en/about
/fr/a-propos
/de/uber
/something-else

I want to test if a given string such as "/about" matches /en/about

more specifically I want to know if it matches "slash + exactly 2 lowercase alpha characters + /about"

I have this working like this:

const routes = [
    '/en/about',
    '/fr/a-propos',
    '/de/uber',
    '/something-else',
];

const regEx = /^(\/[a-z]{2}\b(\/about)\b)$/;

Object.keys(routes).forEach((k) => {
    if (regEx.test(routes[k])) {
        console.log(`redirecting /about to ${routes[k]}`);
    }
});

Now.. very simply.. I want to use a variable instead of hardcoding "/about". I need to put "/about" in a variable and use that to test. I know I'm supposed to use a RegExp to accomplish this, but I've been trying for half an hour and can't figure out how to convert the above regex into one that will work with RegExp and a variable

Appreciate the help!

You must have failed due to the word boundaries that you left as `"\b"` (which is a BACKSPACE char) — Wiktor Stribiżew, Sep 25 '19 at 11:07

score 1 · Accepted Answer · edited Jan 24 '20 at 17:26

You may use it like this code:

const routes = [
    '/en/about',
    '/fr/a-propos',
    '/de/uber',
    '/something-else',
];

const suffix = '/about';
const regEx = new RegExp(`^/[a-z]{2}${suffix}$`);

routes.forEach(k => {
    if (regEx.test(k)) {
        console.log(`redirecting /about to ${k}`);
    }
});

You need RegExp object creation
You may also simplify your forEach loop iteration
There is no need to use a word boundary after ^ or / and before $ or / because / is not a word character and anchors are also boundary matchers.

testing if a string matches a regEx combined with a variable containing slashes

1 Answers1