constructor()

in packages/attribute-slicer/src/lib/VirtualList.ts [75:120]
42 lines of code
12 McCabe index (conditional complexity)

	constructor(config: IConfiguration) {
		const width: string = (config && `${config.w}px`) || "100%";
		const height: string = (config && `${config.h}px`) || "100%";
		this.itemHeight = config.itemHeight;
		this.listContainer = create("div").classed("list-display", true);
		this.scroller = VirtualList.createScroller(0);
		this.container = VirtualList.createContainer(width, height);
		this.container.append(() => this.listContainer.node());
		this.container.append(() => this.scroller.node());
		this.generatorFn = config.generatorFn;
		this.afterRender = config.afterRender;

		// As soon as scrolling has stopped, this interval asynchronouslyremoves all
		// the nodes that are not used anymore
		const cleanNodes = () => {
			if (!this.destroyed) {
				if (Date.now() - this.lastScrolled > 100) {
					const badNodes = this.container.selectAll("[data-rm]");
					if (badNodes.size()) {
						badNodes.remove();
					}
				}
				this.cleanTimeout = setTimeout(cleanNodes, 300);
			}
		};
		this.cleanTimeout = setTimeout(cleanNodes, 300);

		this.container.on("scroll.virtual-list", () => {
			const scrollPos: number = d3Selection.event.target[this.scrollProp]; // Triggers reflow
			if (
				!this.lastRepaintPos ||
				Math.abs(scrollPos - this.lastRepaintPos) > this.maxBuffer
			) {
				const first: number =
					Math.floor(scrollPos / this.itemHeight) - this.screenItemsLen;
				this.renderChunk(this.listContainer, first < 0 ? 0 : first);
				this.lastRepaintPos = scrollPos;
			}

			this.lastScrolled = Date.now();

			if (d3Selection.event.preventDefault) {
				d3Selection.event.preventDefault();
			}
		});
	}