From 2ea7049dd26b13edff42a1b28527db40f2809387 Mon Sep 17 00:00:00 2001
From: Jeremy Likness <jeremy@jeremylikness.com>
Date: Wed, 27 Nov 2019 14:26:18 -0800
Subject: [PATCH] Add declarative data-binding

---
 js/dataBinding.js        | 24 ++++++++++++++++++++++++
 js/slide.js              |  6 +++---
 slides/data-binding.html | 39 ++++++++++++++++++---------------------
 3 files changed, 45 insertions(+), 24 deletions(-)

diff --git a/js/dataBinding.js b/js/dataBinding.js
index 1f09d4d..bcede41 100644
--- a/js/dataBinding.js
+++ b/js/dataBinding.js
@@ -71,6 +71,30 @@ export class DataBinding {
         };
     }
 
+    /**
+     * 
+     * @param {HTMLElement} elem The parent element 
+     * @param {object} context The context to use for binding 
+     */
+    bindAll(elem, context) {
+        this.bindLists(elem, context);
+        this.bindObservables(elem, context);
+    }
+
+    /**
+     * Searches for "data-bind" attribute to data-bind observables
+     * @param {HTMLElement} elem The parent element to search 
+     * @param {object} context The context to use for binding 
+     */
+    bindObservables(elem, context) {
+        const dataBinding = elem.querySelectorAll("[data-bind]");
+        dataBinding.forEach(elem => {
+            this.bindValue(
+                /** @type {HTMLInputElement} */(elem), 
+                context[elem.getAttribute("data-bind")]);
+        });
+    }
+    
     /**
      * Searches for "repeat" attribute to data-bind lists
      * @param {HTMLElement} elem The parent element to search 
diff --git a/js/slide.js b/js/slide.js
index f0f4688..fe7c98b 100644
--- a/js/slide.js
+++ b/js/slide.js
@@ -1,6 +1,6 @@
 // @ts-check
 
-import {DataBinding} from "./dataBinding.js"
+import { DataBinding } from "./dataBinding.js"
 
 /** 
  * Represents a slide 
@@ -21,7 +21,7 @@ export class Slide {
          * Context for embedded scripts
          * @type {object}
          */
-        this._context = {};
+        this._context = { };
         /**
          * Data binding helper
          * @type {DataBinding}
@@ -66,7 +66,7 @@ export class Slide {
         const script = this._html.querySelector("script");
         if (script) {
             this._dataBinding.executeInContext(script.innerText, this._context, true);
-            this._dataBinding.bindLists(this._html, this._context);
+            this._dataBinding.bindAll(this._html, this._context);
         }
     }
 
diff --git a/slides/data-binding.html b/slides/data-binding.html
index a6b6308..fd0d1af 100644
--- a/slides/data-binding.html
+++ b/slides/data-binding.html
@@ -1,30 +1,27 @@
 <title>Data-Binding Example 1</title>
 <h1>Data-Binding Example</h1>
-<label for="first"><div>Number:</div><input type="text" id="first"/></label>
-<label for="second"><div>Multiplied by Number:</div><input type="text" id="second"/></label>
-<label for="result"><div>Result:</div><input type="text" id="result" disabled/></label>
-<label for="firstName"><div>First Name:</div><input type="text" id="firstName"/></label>
-<label for="lastName"><div>Last Name:</div><input type="text" id="lastName"/></label>
-<label for="fullName"><div>Full Name:</div><input type="text" id="fullName" disabled/></label>
+<label for="first"><div>Number:</div><input type="text" id="first" data-bind="n1"/></label>
+<label for="second"><div>Multiplied by Number:</div><input type="text" id="second" data-bind="n2"/></label>
+<label for="result"><div>Result:</div><input type="text" id="result" data-bind="result" disabled/></label>
+<label for="firstName"><div>First Name:</div><input type="text" id="firstName" data-bind="first"/></label>
+<label for="lastName"><div>Last Name:</div><input type="text" id="lastName" data-bind="last"/></label>
+<label for="fullName"><div>Full Name:</div><input type="text" id="fullName" data-bind="full" disabled/></label>
 <br/>
 <ul>
     <li repeat="list" class="appear">{{item.idx}} &mdash; {{item.value}}</li>
 </ul>
 <script>
     this.list = [{idx: 0, value:"one"}, {idx: 1, value:"two"}, {idx: 2, value:"three"}];
-    const bindings = () => {
-        var n1 = this.observable(2);
-        var n2 = this.observable(2);
-        var result = this.computed(() => n1.value*n2.value, [n1, n2]);
-        var first = this.observable("Jeremy");
-        var last = this.observable("");
-        var full = this.computed(() => `${first.value} ${last.value}`.trim(), [first, last]);
-        this.bindValue(document.getElementById("first"), n1);
-        this.bindValue(document.getElementById("second"), n2);
-        this.bindValue(document.getElementById("result"), result);
-        this.bindValue(document.getElementById("firstName"), first);
-        this.bindValue(document.getElementById("lastName"), last);
-        this.bindValue(document.getElementById("fullName"), full);
-    };
-    setTimeout(bindings, 0);
+    const first = this.observable("Jeremy");
+    const last = this.observable("");
+    const n1 = this.observable(2);
+    const n2 = this.observable(4);
+    // assign to context
+    this.n1 = n1;
+    this.n2 = n2;
+    this.first = first;
+    this.last = last;
+    // computed
+    this.result = this.computed(() => n1.value*n2.value, [n1, n2]);
+    this.full = this.computed(() => `${first.value} ${last.value}`.trim(), [first, last]);
 </script>
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