From c7163a055434c9a9c7f15642c134928e236fe39d Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@matrix.org>
Date: Fri, 15 Mar 2019 20:36:04 +0100
Subject: [PATCH] wip of template/databinding

---
 src/ui/web/tree.js | 120 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 src/ui/web/tree.js

diff --git a/src/ui/web/tree.js b/src/ui/web/tree.js
new file mode 100644
index 00000000..6e3ce694
--- /dev/null
+++ b/src/ui/web/tree.js
@@ -0,0 +1,120 @@
+import { setAttribute, addChildren, text } from "./html.js";
+
+function renderTree() {}
+
+
+const tree = renderTree(vm, t => {
+    return t.div({onClick: () => this._clicked(), className: "errorLabel"}, [
+        vm => vm.label,
+        t.span({className: vm => {{fatal: !!vm.fatal}}}, [vm => vm.error])
+    ]);
+});
+
+tree.root
+tree.detach()
+tree.updateBindings(vm);
+
+
+
+
+class Tree {
+    constructor(value, render) {
+        this._ctx = new TreeContext(value);
+        this._root = render(this._ctx);
+    }
+
+    ref(name) {
+        return this._ctx._refs[name];
+    }
+
+    detach() {
+        for (let {node, name, fn} of this._ctx._eventListeners) {
+            node.removeEventListener(name, fn);
+        }
+    }
+}
+
+class TreeContext {
+    constructor(value) {
+        this._value = value;
+        this._refs = {};
+        this._eventListeners = [];
+        this._bindings = [];
+    }
+
+    _addRef(name, node) {
+        this._refs[name] = node;
+    }
+
+    _addEventListener(node, name, fn) {
+        node.addEventListener(name, fn);
+        this._eventListeners.push({node, event, fn});
+    }
+
+    _setAttributeBinding(node, name, fn) {
+        let prevValue = undefined;
+        const binding = () => {
+            const newValue = fn(this._value);
+            if (prevValue !== newValue) {
+                prevValue = newValue;
+                setAttribute(node, name, newValue);
+            }
+        };
+        this._bindings.push(binding);
+        binding();
+    }
+
+    _setTextBinding(fn) {
+        const initialValue = fn(this._value);
+        const node = text(initialValue);
+        let prevValue = initialValue;
+        const binding = () => {
+            const newValue = fn(this._value);
+            if (prevValue !== newValue) {
+                prevValue = newValue;
+                node.textContent = newValue+"";
+            }
+        };
+        this._bindings.push(binding);
+    }
+
+    el(name, attributes, children) {
+        const node = document.createElement(name);
+        for(let [key, value] of Object.entries(attributes)) {
+            const isFn = typeof value === "function";
+            if (key.startsWith("on") && key.length > 2 && isFn) {
+                const eventName = key.substr(2, 1).toLowerCase() + key.substr(3);
+                const handler = value;
+                this._addEventListener(node, eventName, handler);
+            } else if (isFn) {
+                this._addAttributeBinding(node, key, value);
+            } else {
+                setAttribute(node, key, value);
+            }
+        }
+
+        addChildren(node, children);
+        return node;
+    }
+
+    ol(... params)      { return this.el("ol", ... params); }
+    ul(... params)      { return this.el("ul", ... params); }
+    li(... params)      { return this.el("li", ... params); }
+    div(... params)     { return this.el("div", ... params); }
+    h1(... params)      { return this.el("h1", ... params); }
+    h2(... params)      { return this.el("h2", ... params); }
+    h3(... params)      { return this.el("h3", ... params); }
+    h4(... params)      { return this.el("h4", ... params); }
+    h5(... params)      { return this.el("h5", ... params); }
+    h6(... params)      { return this.el("h6", ... params); }
+    p(... params)       { return this.el("p", ... params); }
+    strong(... params)  { return this.el("strong", ... params); }
+    em(... params)      { return this.el("em", ... params); }
+    span(... params)    { return this.el("span", ... params); }
+    img(... params)     { return this.el("img", ... params); }
+    section(... params) { return this.el("section", ... params); }
+    main(... params)    { return this.el("main", ... params); }
+    article(... params) { return this.el("article", ... params); }
+    aside(... params)   { return this.el("aside", ... params); }
+    pre(... params)     { return this.el("pre", ... params); }
+}