CODE EXAMPLE FOR JAVASCRIPT

js regexp match

// 1. Match indices for numbered group
const matchObj = /(a+)(b+)/d.exec('aaaabb');

console.log(matchObj);
/*
Output -
['aaaabb', 'aaaa', 'bb', index: 0, input: 'aaaabb', groups: undefined, indices: Array(3)]
*/
// then
matchObj.indices[1];
/*
Output - 
[0, 4]
*/
// -------------------------

// 2. Match indices for named groups
const matchObj = /(?<as>a+)(?<bs>b+)/d.exec('aaaabb');

console.log(matchObj);
/*
Output - 
['aaaabb', 'aaaa', 'bb', index: 0, input: 'aaaabb', groups: {as: 'aaaa', bs: 'bb'}, indices: Array(3)]
*/
// then
matchObj.indices.groups;
/*
Output -
{ as: [0,4], bs: [4,6] }
*/