JSFiddle - React, Tailwind, and code Playground

JavaScript

var json = [];
    var imgCount = 1;
    var date = 2011;
    var imageSets = 2;
    for(var i = 0; i < imageSets; i++){
     json.push({ "date":date++, 
      "imgs":(function(){ 
       var set = [];
       for(var n = 0; n < 3; n++){
        set.push({"path":"img"+(imgCount++)+".jpg"});
       }
       return set;})()
      });
    }
console.log(json);