const regex = /(?<=<ID>)(\d+)(?=<VAL>)|(?<=<VAL>)[a-z\d]*(?=<ID>)/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(?<=<ID>)(\\d+)(?=<VAL>)|(?<=<VAL>)[a-z\\d]*(?=<ID>)', 'gm')
const str = `<ID>0<VAL>a1b<ID>1<VAL>a2b<ID>2<VAL>a3b<ID>3<VAL>a4b`;
// 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