I would appreciate if someone can help me to come up with a regex that I can look for a pattern in a href. Pattern is to look for a query string hint=value& and then replace it with a new value hint=value2&. so the pattern should start with hint and end with & if there are more query strings or end of the value for hint.
I dont want to use jquery external library (purl). Any help will be much appreciated.
You could use a positive lookahead and check for & or the end of the string.
hint=(.*?)(?=&|$)
Since we're using a lookahead, this means that the replacement doesn't need to include the & at the end. Which might be an important factor if hint=value were to be the last query element.
Which in JavaScript would look like this:
const str = "https://www.sample.com/signup?es=click&hint=m%2A%2A%2A%2A%2A%2A%2Ai%40gmail.com&ru=%2F%22";
const replacement = "hint=newstring";
const regex = /hint=(.*?)(?=&|$)/g;
const result = str.replace(regex, replacement);
console.log(result);Given your example url, then console.log(result) would output:
https://www.sample.com/signup?es=click&hint=newstring&ru=%2F%22
(.*?)& works, but it wouldn't work if hint=value is the last element in the query. Then you could do (.*?)(&|$) however now you need to add & to the end of the replacement if needed. This is why a lookahead (?=&|$) is best. Because here it just checks for the & but never captures it. Thus only replaces what is interesting to you, so to speak.Snippet:
function replaceValue(newValue, url) {
const regex = /\?.*?&((hint)=(.*)?&(.*))/g;
const matches = regex.exec(url);
let result = '';
matches.forEach((matchString , index) => {
if(index === 3) {
result += newValue;
}
else {
result += matchString;
}
});
return result;
}
This would help you
str.replace("hint=value&", "hint=value2&")not enough?value2? Could you give some examples, on a string you want to match, and what you want to replace.