Writing disk after merging existed file

index.js

@@ -1,33 +1,29 @@
+var fs = require('fs');
+var path = require('path');
 var lunr = require('lunr');
 var Entities = require('html-entities').AllHtmlEntities;
 
 var Html = new Entities();
 
-var searchIndex;
 // Called with the `this` context provided by Gitbook
 function getSearchIndex(context) {
-    if (!searchIndex) {
-        // Create search index
-        var ignoreSpecialCharacters = context.config.get('pluginsConfig.lunr.ignoreSpecialCharacters') || context.config.get('lunr.ignoreSpecialCharacters');
-        searchIndex = lunr(function () {
-            this.ref('url');
-
-            this.field('title', { boost: 10 });
-            this.field('keywords', { boost: 15 });
-            this.field('body');
-
-            if (!ignoreSpecialCharacters) {
-                // Don't trim non words characters (to allow search such as "C++")
-                this.pipeline.remove(lunr.trimmer);
-            }
-        });
-    }
-    return searchIndex;
+    // Create search index
+    var ignoreSpecialCharacters = context.config.get('pluginsConfig.lunr.ignoreSpecialCharacters') || context.config.get('lunr.ignoreSpecialCharacters');
+    return lunr(function () {
+        this.ref('url');
+
+        this.field('title', { boost: 10 });
+        this.field('keywords', { boost: 15 });
+        this.field('body');
+
+        if (!ignoreSpecialCharacters) {
+            // Don't trim non words characters (to allow search such as "C++")
+            this.pipeline.remove(lunr.trimmer);
+        }
+    });
 }
 
 // Map of Lunr ref to document
-var documentsStore = {};
-
 var searchIndexEnabled = true;
 var indexSize = 0;
 
@@ -78,21 +74,25 @@ module.exports = {
                 body: text
             };
 
+            var documentsStore = {};
             documentsStore[doc.url] = doc;
-            getSearchIndex(this).add(doc);
 
-            return page;
-        },
+            var targetFile = path.resolve(this.output.root(), 'search_index.json');
+            var targetJSON = JSON.parse(fs.existsSync(targetFile) ? fs.readFileSync(targetFile, { encoding: 'utf8' }) : '{"index":{},"store":{}}');
+
+            var searchIndex = targetJSON.index.documentStore ?
+                lunr.Index.load(targetJSON.index)
+                : getSearchIndex(this);
 
-        // Write index to disk
-        'finish': function() {
-            if (this.output.name != 'website') return;
+            searchIndex.remove(doc);
+            searchIndex.add(doc);
 
-            this.log.debug.ln('write search index');
-            return this.output.writeFile('search_index.json', JSON.stringify({
-                index: getSearchIndex(this),
-                store: documentsStore
+            this.output.writeFile('search_index.json', JSON.stringify({
+                index: searchIndex,
+                store: Object.assign(targetJSON.store, documentsStore)
             }));
+
+            return page;
         }
     }
 };

package.json

@@ -1,8 +1,8 @@
 {
-  "name": "gitbook-plugin-lunr",
+  "name": "@aleen42/gitbook-plugin-lunr",
   "description": "Index book in a lunr index accessible from the search plugin",
   "main": "index.js",
-  "version": "1.2.0",
+  "version": "1.0.0",
   "engines": {
     "gitbook": ">=3.0.0-pre.0"
   },