constructor (config) {
    super();
    checkParams(config);

    if (config.container instanceof HTMLElement) {
      this.container = config.container;
      this.containerClass = config.container.className;
    }
    else {
      this.containerClass = config.container;
      this.container = document.querySelector(config.container);
    }

    this.static = config.static || false;
    this.size = config.items;
    this.gutter = config.gutter;
    this.maxColumns = config.maxColumns || false;
    this.useMin = config.useMin || false;
    this.useTransform = config.useTransform;
    this.animate = config.animate || false;
    this.center = config.center;
    this.styledItems = new Set();
    this.resizeObserver = null;
    this.isPositioning = false;
  }
Initializes the necessary variables
for a magic grid.

@param config - configuration object