Typescript react -Object is possibly nil

Question

I'm super new to react and I've been asked to help out a react typescript website. At the moment my matches const is returning an Object is possibly 'null'. I've tried making my match constant null but for the life of me I cannot figure out how to work around this not to get this error. Any help would be much appreciated.

 case "text":
      return (
        <div>
          {" "}
          {note.text.map((content: string, idx: number) => {
            const result = [];
            const matches = content.match(
              /(.*?)(<a href=")?(https?|www)((".*?>.*?<\/a>)|[^\s>]?)*(.*?)/gi
            );

            if (!!matches) {
              matches.forEach((match) => {
                let link;
                if (/href="/i.test(match)) {
                  const url = match 
                    .match(/<a href="(.*?)(?=">)/i)[0]
                    .replace('<a href="', "");
                  const linkText = match
                    .match(/(?:<a href=".*?">)(.*)(?=<\/a>)/)[0]
                    .replace(/(?:<a href=".*?">)/i, "");
                  link = <a href={url}>{linkText}</a>;
                } else {
                  const url = match.match(/(https?|www)[^\s]*/gi).join("");
                  link = <a href={url}>{url}</a>;
                }

                const splitter = match.match(
                  /(<a href=")?(https?|www)[^\s]*(.*<\/a>)?/gi
                )[0];
                const paredPlainText = match.split(new RegExp(splitter));
                result.push(paredPlainText[0]);
                result.push(link);
                result.push(paredPlainText[1]);
              });
            } else {
              result.push(content);
            }

            return <p>{result}</p>;
          })}
        </div>
      );

Answer 1

I'm not fully sure I understand your problem, the description sounds a bit confuse, but I believe you mean that line:

if (!!matches) {

right?

This converts the result of the match call (which can be an array with results or null ) to a bool. Just use

if (matches) {

instead, which checks for a truthy expression ( null represents a falsy result).

If this answer is not what you are after then please add more description to your question.

Answer 2

Thanks everyone for the response! This was my answer using non-null assertion operator ! after the .match as below

case "text":
      return (
        <div>
          {" "}
          {note.text.map((content: string, idx: number) => {
            const result = [];
            const matches = content.match(
              /(.*?)(<a href=")?(https?|www)((".*?>.*?<\/a>)|[^\s>]?)*(.*?)/gi
            );

            if (!!matches) {
              matches.forEach((match) => {
                let link;
                if (/href="/i.test(match)) {
                  const url = match
                    .match(/<a href="(.*?)(?=">)/i)![0]
                    .replace('<a href="', "");
                  const linkText = match
                    .match(/(?:<a href=".*?">)(.*)(?=<\/a>)/)![0]
                    .replace(/(?:<a href=".*?">)/i, "");
                  link = <a href={url}>{linkText}</a>;
                } else {
                  const url = match.match(/(https?|www)[^\s]*/gi)!.join("");
                  link = <a href={url}>{url}</a>;
                }

                const splitter = match.match(
                  /(<a href=")?(https?|www)[^\s]*(.*<\/a>)?/gi
                )![0];
                const paredPlainText = match.split(new RegExp(splitter));
                result.push(paredPlainText[0]);
                result.push(link);
                result.push(paredPlainText[1]);

              });
            } else {
              result.push(content)
            }
            console.log(result);

            return <p>{result}</p>;
          })}
        </div>
      );