@surface/custom-element/internal/aot/block.js

Provides support of directives and data binding on custom elements.

import { enumerateRange } from "../common.js";
import { disposeTree } from "../singletons.js";
const BLOCKS = Symbol("custom-element:block");
export default class Block {
    constructor() {
        this.disposed = false;
        this.start = document.createComment("#start");
        this.end = document.createComment("#end");
        this.start[BLOCKS] = new Set([this]);
        this.end[BLOCKS] = new Set([this]);
    }
    isAnchor(node) {
        return !!node[BLOCKS];
    }
    optimize() {
        const hasNestedDirective = this.start.nextSibling
            && this.start.nextSibling != this.end
            && this.isAnchor(this.start.nextSibling)
            && this.end.previousSibling
            && this.end.previousSibling != this.start
            && this.isAnchor(this.end.previousSibling);
        if (hasNestedDirective) {
            const nextOpen = this.start.nextSibling;
            const previousClose = this.end.previousSibling;
            const open = this.start;
            const close = this.end;
            for (const block of open[BLOCKS].values()) {
                block.start = nextOpen;
                nextOpen[BLOCKS].add(block);
            }
            for (const block of close[BLOCKS].values()) {
                block.end = previousClose;
                previousClose[BLOCKS].add(block);
            }
            open.remove();
            close.remove();
        }
    }
    connect(node) {
        node.appendChild(this.start);
        node.appendChild(this.end);
    }
    clear() {
        for (const element of enumerateRange(this.start, this.end)) {
            element.remove();
            disposeTree(element);
        }
    }
    dispose() {
        if (!this.disposed) {
            this.clear();
            if (this.start[BLOCKS].size == 1) {
                this.start.remove();
            }
            else {
                this.start[BLOCKS].delete(this);
            }
            if (this.end[BLOCKS].size == 1) {
                this.end.remove();
            }
            else {
                this.end[BLOCKS].delete(this);
            }
            this.disposed = true;
        }
    }
    insertAt(parent, reference) {
        parent.replaceChild(this.end, reference);
        parent.insertBefore(this.start, this.end);
    }
    setContent(content, optimize = true) {
        this.end.parentNode.insertBefore(content, this.end);
        if (optimize) {
            this.optimize();
        }
    }
}