empty fragment does not break

cjs/index.js

@@ -23,10 +23,8 @@ exports.diffable = diffable;
 const persistent = fragment => {
   const {childNodes} = fragment;
   const {length} = childNodes;
-  // If the fragment has no content
-  // it should return undefined and break
   if (length < 2)
-    return childNodes[0];
+    return length ? childNodes[0] : fragment;
   const nodes = slice.call(childNodes, 0);
   const firstChild = nodes[0];
   const lastChild = nodes[length - 1];

esm/index.js

@@ -21,10 +21,8 @@ export const diffable = (node, operation) => node.nodeType === nodeType ?
 export const persistent = fragment => {
   const {childNodes} = fragment;
   const {length} = childNodes;
-  // If the fragment has no content
-  // it should return undefined and break
   if (length < 2)
-    return childNodes[0];
+    return length ? childNodes[0] : fragment;
   const nodes = slice.call(childNodes, 0);
   const firstChild = nodes[0];
   const lastChild = nodes[length - 1];

index.js

@@ -22,10 +22,8 @@ var uwire = (function (exports) {
   };
   var persistent = function persistent(fragment) {
     var childNodes = fragment.childNodes;
-    var length = childNodes.length; // If the fragment has no content
-    // it should return undefined and break
-
-    if (length < 2) return childNodes[0];
+    var length = childNodes.length;
+    if (length < 2) return length ? childNodes[0] : fragment;
     var nodes = slice.call(childNodes, 0);
     var firstChild = nodes[0];
     var lastChild = nodes[length - 1];

package.json

@@ -8,7 +8,7 @@
     "cjs": "ascjs esm cjs",
     "rollup:es": "rollup --config rollup/es.config.js",
     "rollup:babel": "rollup --config rollup/babel.config.js",
-    "min": "uglifyjs index.js --support-ie8 --comments=/^!/ -c -m -o min.js",
+    "min": "terser index.js --comments=/^!/ -c -m -o min.js",
     "coveralls": "nyc report --reporter=text-lcov | coveralls",
     "test": "nyc node test/index.js"
   },
@@ -21,17 +21,17 @@
   "author": "Andrea Giammarchi",
   "license": "ISC",
   "devDependencies": {
-    "@babel/core": "^7.8.7",
-    "@babel/preset-env": "^7.8.7",
-    "ascjs": "^3.1.2",
-    "basichtml": "^2.1.4",
-    "coveralls": "^3.0.9",
-    "nyc": "^15.0.0",
-    "rollup": "^2.0.5",
+    "@babel/core": "^7.11.4",
+    "@babel/preset-env": "^7.11.0",
+    "ascjs": "^4.0.1",
+    "basichtml": "^2.3.0",
+    "coveralls": "^3.1.0",
+    "nyc": "^15.1.0",
+    "rollup": "^2.26.5",
     "rollup-plugin-babel": "^4.4.0",
     "rollup-plugin-node-resolve": "^5.2.0",
-    "rollup-plugin-terser": "^5.3.0",
-    "uglify-js": "^3.8.0"
+    "rollup-plugin-terser": "^7.0.0",
+    "terser": "^5.2.1"
   },
   "module": "./esm/index.js",
   "type": "module",

test/index.js

@@ -3,7 +3,10 @@ const {document} = require('basichtml').init();
 const {diffable, persistent} = require('../cjs');
 
 const fragmentSingle = document.createDocumentFragment();
-fragmentSingle.appendChild(document.createTextNode('a'));
+console.assert(persistent(fragmentSingle) === fragmentSingle, 'no childNodes');
+
+const a = fragmentSingle.appendChild(document.createTextNode('a'));
+console.assert(persistent(fragmentSingle) === a, 'a childNode');
 
 const fragmentMulti = document.createDocumentFragment();
 fragmentMulti.appendChild(document.createTextNode('a'));