update elements and fix some bugs

lib/src/prism/plugins/line-numbers/prism-line-numbers.js

Index: lib/src/prism/plugins/line-numbers/prism-line-numbers.js
diff --git a/lib/src/prism/plugins/line-numbers/prism-line-numbers.js b/lib/src/prism/plugins/line-numbers/prism-line-numbers.js
index 9443deb7dc53690eaacaa17f96a4e956a5ff2193..8323a43b13dd56c5fccf2ff473ff95e5fbdb8a0b 100644
--- a/lib/src/prism/plugins/line-numbers/prism-line-numbers.js
+++ b/lib/src/prism/plugins/line-numbers/prism-line-numbers.js
@@ -1,15 +1,30 @@
-Prism.hooks.add('after-highlight', function (env) {
+(function() {
+
+if (typeof self === 'undefined' || !self.Prism || !self.document) {
+	return;
+}
+
+Prism.hooks.add('complete', function (env) {
+	if (!env.code) {
+		return;
+	}
+
 	// works only for <code> wrapped inside <pre> (not inline)
 	var pre = env.element.parentNode;
 	var clsReg = /\s*\bline-numbers\b\s*/;
 	if (
 		!pre || !/pre/i.test(pre.nodeName) ||
-		// Abort only if nor the <pre> nor the <code> have the class
+			// Abort only if nor the <pre> nor the <code> have the class
 		(!clsReg.test(pre.className) && !clsReg.test(env.element.className))
 	) {
 		return;
 	}
 
+	if (env.element.querySelector(".line-numbers-rows")) {
+		// Abort if line numbers already exists
+		return;
+	}
+
 	if (clsReg.test(env.element.className)) {
 		// Remove the class "line-numbers" from the <code>
 		env.element.className = env.element.className.replace(clsReg, '');
@@ -19,10 +34,11 @@ Prism.hooks.add('after-highlight', function (env) {
 		pre.className += ' line-numbers';
 	}
 
-	var linesNum = (1 + env.code.split('\n').length);
+	var match = env.code.match(/\n(?!$)/g);
+	var linesNum = match ? match.length + 1 : 1;
 	var lineNumbersWrapper;
 
-	var lines = new Array(linesNum);
+	var lines = new Array(linesNum + 1);
 	lines = lines.join('<span></span>');
 
 	lineNumbersWrapper = document.createElement('span');
@@ -35,4 +51,6 @@ Prism.hooks.add('after-highlight', function (env) {
 
 	env.element.appendChild(lineNumbersWrapper);
 
-});
+});
+
+}());