const regex = /(path)(?:$|\?(?:(?=.*\b(foo=)(\d+)\b.*$)|(?!foo=).*?))/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(path)(?:$|\\?(?:(?=.*\\b(foo=)(\\d+)\\b.*$)|(?!foo=).*?))', 'gm')
const str = `path?foo=67
path?foo=67&bar=hello
path?bar=bye&foo=1&baz=12
path?bar=123
path
path?foo=37signals
path?foo=-8
something?foo=1`;
// 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