add live data-binding with Snoopy

Daniel-Hug · Daniel-Hug · commit 47d03313691e · 2016-01-20T14:57:27.000-08:00
diff --git a/README.md b/README.md
@@ -54,12 +54,45 @@ var label = dom({
 document.body.appendChild(label);
 ```
 
+
+### Get live DOM updates with [Snoopy](https://github.com/Daniel-Hug/snoopy)
+
+1. include [Snoopy](https://github.com/Daniel-Hug/snoopy) before DOM builder:
+
+	```html
+	<script src="path/to/snoopy.js"></script>
+	```
+
+2. stick data in a Snoopy instance
+
+	```js
+	var counter = Snoopy({count: 0});
+	```
+
+3. live-bind data with DOM-Builder
+
+	```js
+	var button = dom({
+		el: 'button',
+		text: counter.snoop('count'),
+		on_click: function() {
+			counter.set('count', counter.count + 1);
+		}
+	});
+	```
+
+
 ### node values
 
 Node values can be any of the following:
- - **object:** creates an element
- - **string:** creates a text node
- - **DOM node without parent:** uses the node
+ - **object:** renders an element
+ - **string or number:** renders a text node
+ - **DOM node without parent:** renders the existing node
+ - **array of node values:** renders a document fragment
+ - **"snoopable" function ([Snoopy](#get-live-dom-updates) makes this easy):**
+   1. should accept a callback
+   2. call it right away passing a node value
+   3. call it again whenever the node value should change
 
 
 ### properties
diff --git a/dom.js b/dom.js
@@ -11,6 +11,15 @@
 })(this, function() {
 	'use strict';
 
+	function bindSet(val, setter) {
+		// if val is function it's snoopable so the setter should be passed to it.
+		if (typeof val === 'function') {
+			val(setter);
+		} else {
+			setter(val);
+		}
+	}
+	
 	function createDocFrag(array) {
 		// build each node and stick in docFrag
 		var docFrag = document.createDocumentFragment();
@@ -21,14 +30,35 @@
 		return docFrag;
 	}
 
+
+	// snoopable fn should:
+	//  - accept a callback
+	//  - call it right away passing a node value
+	//  - call it again whenever the node value should change
+	function createDataBoundNode(fn) {
+		var node;
+		fn(function(newVal) {
+			//if (node instanceof HTMLElement && newVal.el === node.tagName) {
+				// take props from newVal and stick on node
+			//}
+			var newNode = dom(newVal);
+			if (node) node.parentNode.replaceChild(newNode, node);
+			node = newNode;
+		});
+		return node;
+	}
+	
 	function createEl(elData) {
 		var el = document.createElement(elData.el || 'div');
 
 		Object.keys(elData).forEach(function(key) {
 			if (['el', 'text', 'kids'].indexOf(key) === -1) {
 				// set JS properties
 				if (key[0] === '_') {
-					el[key.slice(1)] = elData[key];
+					var prop = key.slice(1);
+					bindSet(elData[key], function(newVal) {
+						el[prop] = newVal;
+					});
 				}
 
 				// add event listener(s)
@@ -46,12 +76,20 @@
 				}
 
 				// add html attributes
-				else el.setAttribute(key, elData[key]);
+				else {
+					bindSet(elData[key], function(newVal) {
+						el.setAttribute(key, newVal);
+					});
+				}
 			}
 		});
 
 		// set text
-		if (elData.text) el.textContent = elData.text;
+		if (elData.text) {
+			bindSet(elData.text, function(newVal) {
+				el.textContent = newVal;
+			});
+		}
 
 		// otherwise add child nodes
 		else if (elData.kids) el.appendChild(createDocFrag(elData.kids));
@@ -72,6 +110,9 @@
 		// array -> document fragment
 		Array.isArray(nodeData) ? createDocFrag(nodeData) :
 
+		// function -> data bound DOM node
+		type === 'function' ? createDataBoundNode(nodeData) :
+
 		// object -> element
 		createEl(nodeData);
 	};
diff --git a/index.html b/index.html
@@ -5,28 +5,49 @@
 	<title>DOM Builder demo</title>
 </head>
 <body>
+	<script src="snoopy.js"></script>
 	<script src="dom.js"></script>
 
 	<script>
-	var input = dom({
-		el: "input",
-		type: "text",
-		placeholder: "type something",
-		_autofocus: true
+	// setup observable data
+	var counter = new Snoopy({count: 0});
+
+	// counter.even subscribes to counter.count
+	counter.snoop('count', function(val) {
+		counter.set('even', val % 2 === 0);
+	});
+
+	counter.snoop('even', function(even) {
+		counter.set('evenText', even ? 'even.' : 'not even.');
 	});
-	var output = dom({ el: 'output' });
 
-	document.body.appendChild(dom([
+	// <button>0</button>
+	var button = dom([
 		{
-			el: 'form',
-			on_submit: function(event) {
-				event.preventDefault();
-				output.textContent = input.value ? ' Text: ' + input.value : '';
-			},
-			kids: [ input, { el: 'button', text: 'Go' } ]
+			el: 'button',
+			text: counter.snoop('count'),
+			on_click: function() {
+				counter.set('count', counter.count + 1);
+			}
 		},
-		output
-	]));
+		{
+			el: 'label',
+			kids: [
+				' ',
+				{
+					el: 'input',
+					type: 'checkbox',
+					_checked: counter.snoop('even'),
+					_disabled: true
+				},
+				counter.snoop('count'), ' is ',
+				counter.snoop('evenText')
+			]
+		}
+	]);
+
+	// append to <body>
+	document.body.appendChild(button);
 	</script>
 </body>
 </html>
