# HG changeset patch
# User cin
# Date 2022-08-10 20:27:03
# Node ID 131e369d1143346d0870f576f5da2423cf17c1c2
# Parent  d99e2014cea4f44cc1931f8caf944c05755822c0

Added Renderer, WatchRendition

diff --git a/djx/src/main/ts/tsx/Renderer.ts b/djx/src/main/ts/tsx/Renderer.ts
new file mode 100644
--- /dev/null
+++ b/djx/src/main/ts/tsx/Renderer.ts
@@ -0,0 +1,26 @@
+import { Scope } from "./Scope";
+import { destroy, Rendition } from "./traits";
+
+let _scope = Scope.dummy;
+
+const beginRender = async () => {
+}
+
+const endRender = () => {
+}
+
+export const getScope = () => _scope;
+
+export const render = async (rendition: () => Rendition, scope = Scope.dummy) => {
+    await beginRender();
+    const prev = _scope;
+    _scope = scope;
+    try {
+        const node = rendition().getDomNode();
+        scope.own(() => destroy(node));
+        return node;
+    } finally {
+        _scope = prev;
+        endRender();
+    }
+}
diff --git a/djx/src/main/ts/tsx/Scope.ts b/djx/src/main/ts/tsx/Scope.ts
new file mode 100644
--- /dev/null
+++ b/djx/src/main/ts/tsx/Scope.ts
@@ -0,0 +1,40 @@
+import { IDestroyable, IRemovable } from "@implab/core-amd/interfaces";
+import { isDestroyable, isRemovable } from "@implab/core-amd/safe";
+
+export interface IScope {
+    own(target: (() => void) | IDestroyable | IRemovable): void;
+}
+
+export class Scope implements IDestroyable, IScope {
+    private readonly _cleanup: (() => void)[] = [];
+
+    static readonly dummy: IScope = { own() { } };
+
+    own(target: (() => void) | IDestroyable | IRemovable) {
+        if (target instanceof Function) {
+            this._cleanup.push(target);
+        } else if (isDestroyable(target)) {
+            this._cleanup.push(() => target.destroy());
+        } else if (isRemovable(target)) {
+            this._cleanup.push(() => target.remove());
+        }
+    }
+
+    clean() {
+        const guard = (cb: () => void) => {
+            try {
+                cb();
+            } catch {
+                // guard
+            }
+        }
+
+        this._cleanup.forEach(guard);
+        this._cleanup.length = 0;
+    }
+
+    destroy() {
+        this.clean();
+    }
+
+}
\ No newline at end of file
diff --git a/djx/src/main/ts/tsx/WatchRendition.ts b/djx/src/main/ts/tsx/WatchRendition.ts
new file mode 100644
--- /dev/null
+++ b/djx/src/main/ts/tsx/WatchRendition.ts
@@ -0,0 +1,58 @@
+import { id as mid } from "module";
+import { TraceSource } from "@implab/core-amd/log/TraceSource";
+import { argumentNotNull } from "@implab/core-amd/safe";
+import { place } from "dojo/dom-construct";
+import { getScope, render } from "./Renderer";
+import { RenditionBase } from "./RenditionBase";
+import { Scope } from "./Scope";
+import { locateNode } from "./traits";
+
+const trace = TraceSource.get(mid);
+
+export class WatchRendition<T> extends RenditionBase<Node> {
+    private readonly _factory: (arg: T) => any;
+
+    private _node: Node;
+
+    private readonly _scope = new Scope();
+
+    constructor(component: (arg: T) => any, subject: any) {
+        super();
+        argumentNotNull(component, "component");
+
+        this._factory = component;
+
+        this._node = document.createComment("WatchRendition placeholder");
+    }
+
+    protected _create(attrs: object, children: any[]) {
+        const _attrs: any = attrs || {};
+        const _children = children.map(x => this.getItemDom(x));
+        this._node = this.getItemDom(
+            this._factory.call(null, { ..._attrs, children: _children })
+        );
+
+        const scope = getScope();
+        scope.own(this._scope);
+
+        // если отрендерили текст? или DocumentFragment
+    }
+
+    private async _render(value: T) {
+        const [refNode, position] = locateNode(this._node);
+        this._scope.clean();
+
+        this._node = await render(() => this._factory(value), this._scope);
+
+        if (refNode)
+            place(this._node, refNode, position);
+    }
+
+    protected _getDomNode() {
+        if (!this._node)
+            throw new Error("The instance of the widget isn't created");
+        return this._node;
+    }
+
+
+}
diff --git a/djx/src/main/ts/tsx/traits.ts b/djx/src/main/ts/tsx/traits.ts
--- a/djx/src/main/ts/tsx/traits.ts
+++ b/djx/src/main/ts/tsx/traits.ts
@@ -8,6 +8,8 @@ type _WidgetBaseConstructor = typeof _Wi
 
 export type DojoNodePosition = "first" | "after" | "before" | "last" | "replace" | "only" | number;
 
+export type DojoNodeLocation = [Node | null, DojoNodePosition];
+
 export interface Rendition<TNode extends Node = Node> {
     getDomNode(): TNode;
 
@@ -150,3 +152,10 @@ export function startupWidgets(target: N
             target.startup();
     }
 }
+
+export function locateNode(node: Node): DojoNodeLocation {
+    const next = node.nextSibling;
+    return next ?
+        [next, "before"] : 
+        [node.parentNode, "last"];
+}
\ No newline at end of file