Aframe register component question

gistfile1.txt

AFRAME.registerComponent('voxelarena', {
  init: function () {
    var parentEl = this.el;
    var col_ind = 0;
    var row_ind = 0;
    var num_tiles = 0;

    setInterval(function () {
      if(num_tiles >= 7*7) return;
      var childEl = document.createElement('a-entity');
      childEl.setAttribute('mixin', 'voxel');
      childEl.setAttribute('position', {x: col_ind+x_pos, y: 0, z: row_ind+z_pos});
      childEl.setAttribute('changecolour', {tileindex: num_tiles});
      parentEl.appendChild(childEl);
      col_ind++;
      if(col_ind >= 7) {
        row_ind++;
        col_ind = 0;
      }
      if(col_ind >= 7) {
        row_ind = 0;
      }
      num_tiles++;
    }, 50);
  }
});

AFRAME.registerComponent('changecolour', {
  schema: {
    tileindex: {type: 'number', default: -1}
  },
  init: function () {
    this.el.setAttribute('material', 'color', '#CC00CC');
    console.log(this.data.tileindex);
  },
  tick: function (time, timeDelta) {

    if(time-last_change >= 100) {

      if(hue_dir) {
        hue_val += 10;
      } else {
        hue_val -= 10;
      }

      if(hue_val < stop_hue) {
        hue_val = stop_hue;
        hue_dir = !hue_dir;
      } else if(hue_val > start_hue) {
        hue_val = start_hue;
        hue_dir = !hue_dir;
      }

      var hsv = {
        h: hue_val,
        s: 100,
        v: 80
      };
      var myHsvColor = Color().fromHsv( hsv );

      this.el.setAttribute('material', 'color', myHsvColor.toCSS());

      console.log("ind = " + this.data.tileindex + " hue = " + hue_val + " time = " + time + " & delta = " + timeDelta);
      last_change = time;
    }
  }
});