How to get all possible overlapping matches for a string

Question

I\'m working on the MIU system problem from \"Gödel, Escher, Bach\" chapter 2.

One of the rules states

Rule III: If III occurs in one of the strings in

Answer 1

Sometimes regexes are overkill. In your case a simple indexOf might be fine too!

Here is, admittedly, a hack, but you can transform it into pretty, reusable code on your own:

var s = "MIIIIIUIUIIIUUIIUIIIIIU";
var results = [];
for (var i = 0; true; i += 1) {
    i = s.indexOf("III", i);
    if (i === -1) {
        break;
    }
    results.push(i);
}
console.log("Match positions: " + JSON.stringify(results));

It takes care of overlaps just fine, and at least to me, the indexOf just looks simpler.