How to use the fastdom.write function in fastdom

fastdom.read(() => {
        // Our grid is a square, set the height of the grid wrapper
        // to the width of the grid wrapper
        fastdom.write(() => {
          this.$gridWrapper.css(
            'height',
            `${this.$gridWrapper.offset().width}px`,
          );
        });
        this.gridHeightIsSet = true;
      });
    } else if (this.gridHeightIsSet) {

Cast.prototype.renderNew = function(block){
  this.emit('render', block)
  fastdom.write(function(){
    this.el.appendChild(block.el);
  }.bind(this));
  fastdom.defer(block.show.bind(block));
};

Block.prototype.hide = function(fn){
  if (this.hidden) return;
  fastdom.write(function(){
    if (fn) afterTransition.once(this.el, fn);
    this.classes.add('hidden');
    this.el.setAttribute('aria-hidden', true);
  }.bind(this));
  this.hidden = true;
  return this;
};

Block.prototype.hide = function(fn){
  if (this.hidden) return;
  fastdom.write(function(){
    if (fn) afterTransition.once(this.el, fn);
    this.classes.add('hidden');
    this.el.setAttribute('aria-hidden', true);
  }.bind(this));
  this.hidden = true;
  return this;
};

setTimeout(() => {
    clearInterval(interval);
    fastdom.write(() => $container.scrollTop(offset));
  }, duration);
};