Add lunr.js options when building the index

Author: Darkle

README.md

@@ -77,6 +77,7 @@ API
 * [Minimum should match (mm)](#minimum-should-match-mm)
 * [Filtering documents](#filtering-documents)
 * [Building the index](#building-the-index)
+* [Passing Options to lunr.js during build](#passing-options-to-lunr.js-during-build)
 * [Deleting the index](#deleting-the-index)
 * [Stale queries](#stale-queries)
 * [Other languages](#other-languages)
@@ -422,6 +423,23 @@ This will build up the index without querying it. If the database has changed si
 
 You must at least provide the `fields` you want to index.  If the language isn't English, you must pass in the `language` option.  Boosts don't matter.
 
+### Passing Options to lunr.js during build
+
+You can pass in options to lunr.js during the index build by adding a `lunrOptions` option to the search. `lunrOptions` is a function whereby you can access the lunr instance via `this` from within the function. For example, if you wanted to add a function to the pipeline, you could do it like so:
+
+```js
+pouch.search({
+  fields: ['title', 'text'],
+  build: true,
+  lunrOptions: function(){
+    this.pipeline.add(function (token, tokenIndex, tokens) {
+      // text processing in here
+    })
+  }
+});
+```
+More info on the lunr.js methods available here: http://lunrjs.com/docs/
+
 ### Deleting the index
 
 If, for whatever reason, you need to delete an index that's been saved to disk, you can pass in `{destroy: true}` to the `search()` function, and instead of searching, it will delete the external search database.

index.js

@@ -102,6 +102,7 @@ exports.search = utils.toPromise(function (opts, callback) {
   var stale = opts.stale;
   var limit = opts.limit;
   var build = opts.build;
+  var lunrOptions = build ? opts.lunrOptions : null;
   var skip = opts.skip || 0;
   var language = opts.language || 'en';
   var filter = opts.filter;
@@ -125,7 +126,7 @@ exports.search = utils.toPromise(function (opts, callback) {
 
   var index = indexes[language];
   if (!index) {
-    index = indexes[language] = lunr();
+    index = indexes[language] = lunr(lunrOptions);
     if (language !== 'en') {
       index.use(global.lunr[language]);
     }