const regex = /(?<![\p{L}0-9])([#＃][·・ー_0-9０-９a-zA-Zａ-ｚＡ-Ｚぁ-んァ-ン一-龠]{1,24})(?![\p{L}0-9])/gu;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(?<![\\p{L}0-9])([#＃][·・ー_0-9０-９a-zA-Zａ-ｚＡ-Ｚぁ-んァ-ン一-龠]{1,24})(?![\\p{L}0-9])', 'gu')
const str = `Hashtag must be started with # character.
Hashtag will be detected by space character and other special characters (!,@,&,*,%,\$).
Example 1: Hello#guys. This is a #test. -> Valid hashtag: #test.
Example 2: Hello#guys. This is a #test!#message. -> Valid hashtag: #test and #message
Example 3: Hello#guys. This is a #test #message. -> Valid hashtag: #test and #message
Example 4: Hello#guys. This is a #test#message. -> Valid hashtag: #test
Example 5: #asdasdasdasdasdasdasdasdasd -> Valid hashtag: none
Example 6: # -> Valid hashtag: none
#日本語#asd => Valid hashtag should be #日本語
#日本語日本語日本語日本語日本語日本語日本語日本語日本語 => Will not a valid hashtag`;
// Reset `lastIndex` if this regex is defined globally
// regex.lastIndex = 0;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions