prototype alternate datastructure for trees in listmap

www/common/flat-dom.js

@@ -0,0 +1,79 @@
+define([], function () {
+    var Flat = {};
+
+    var slice = function (coll) {
+        return Array.prototype.slice.call(coll);
+    };
+
+    var getAttrs = function (el) {
+        var i = 0;
+        var l = el.attributes.length;
+        var attr;
+        var data = {};
+        for (;i < l;i++) {
+            attr = el.attributes[i];
+            if (attr.name && attr.value) { data[attr.name] = attr.value; }
+        }
+        return data;
+    };
+
+    Flat.fromDOM = function (dom) {
+        var data = {
+            map: {},
+        };
+
+        var i = 1; // start from 1 so we're always truthey
+        var uid = function () { return i++; };
+
+        var process = function (el) {
+            if (!el || el.attributes) { return void console.error(el); }
+            var id = uid();
+            if (!el.tagName && el.nodeType === Node.TEXT_NODE) {
+                data.map[id] = el.textContent;
+                return id;
+            }
+            data.map[id] = [
+                el.tagName,
+                getAttrs(el),
+                slice(el.childNodes).map(function (e) {
+                    return process(e);
+                })
+            ];
+            return id;
+        };
+
+        data.root = process(dom);
+        return data;
+    };
+
+    Flat.toDOM = function (data) {
+        var visited = {};
+        var process = function (key) {
+            if (visited[key]) {
+                // TODO handle this more gracefully.
+                throw new Error('duplicate id or loop detected');
+            }
+            visited[key] = true; // mark paths as visited.
+
+            var hj = data.map[key];
+            if (typeof(hj) === 'string') { return document.createTextNode(hj); }
+            if (typeof(hj) === 'undefined') { return; }
+            if (!Array.isArray(hj)) { console.error(hj); throw new Error('expected array'); }
+
+            var e = document.createElement(hj[0]);
+            for (var x in hj[1]) { e.setAttribute(x, hj[1][x]); }
+            var child;
+            for (var i = 0; i < hj[2].length; i++) {
+                child = process(hj[2][i]);
+                if (child) {
+                    e.appendChild(child);
+                }
+            }
+            return e;
+        };
+
+        return process(data.root);
+    };
+
+    return Flat;
+});