JSFiddle - React, Tailwind, and code Playground

JavaScript

data = 'Colour3/43"';

for (var i = 0; i < 5; i++)
{
    var patt1 = new RegExp('Colour' + i + '/(\\d+)"'),
        ab = (data.match(patt1) || [])[1]; 
    
    console.log(ab);
}