How can I check a string starts with a certain substring and ends with a certain substring using reg-CodePudding

I want to check that an input string is a valid shareable Google Forms URL. The requirement is that the input string starts with 'https://docs.google.com/forms/' and ends with 'viewform?usp=sf_link'. I would like to use the .match() with a regex function to accomplish this.

My current function is

isFormsUrl(inputString) {
   return inputString.startsWith('https://docs.google.com/forms/') && inputString.endsWith('viewform?usp=sf_link');
}

This function works but I'd like to use regex match() instead of the startsWith() and endsWith() functions to stay consistent with my current codebase. I am very unfamiliar with regex. Thanks!

CodePudding user response：

You can do this using the RegExp test method, which returns true if the string matches the regex.

Note that many characters need to be "escaped" in regex using a backstroke "", namely, ^$/\.? * though that list is not exhaustive.

You can also use the start and end anchors ^ and $ respectively to specify that the string should match at the start and end.

Combined this is the result:

const strings = [
  "https://docs.google.com/forms/viewform?usp=sf_link",
  "https://docs.google.com/forms/ LITERALLY ANYTHING viewform?usp=sf_link",
  "https://docs.google.com/forms/viewform",
  "https://docs.notQuiteRight.com/forms/viewform?usp=sf_link$",
];
const regex = /^https:\/\/docs\.google\.com\/forms\/.*viewform\?usp=sf_link$/;

for (let s of strings) {
  console.log(s, regex.test(s));
}

CodePudding user response：

Try this:

/^https:\/\/docs\.google\.com\/forms\/. viewform\?usp=sf_link$/.test(yourString);

. means there must be at least one character inbetween. If empty is acceptable, you can replace it with .*.