search performance: Stop at max_items.

Once we have max_items results, stop trying
to get more items.

This should really help large realms when
you do a search on streams that turns up
more than N streams (where N is about 12).
We won't even bother to find people.

frontend_tests/node_tests/search.js

@@ -85,9 +85,11 @@ run_test('initizalize', () => {
         return 'is:starred';
     };
 
+    search_suggestion.max_num_of_search_results = 99;
     search_query_box.typeahead = (opts) => {
+
         assert.equal(opts.fixed, true);
-        assert.equal(opts.items, 12);
+        assert.equal(opts.items, 99);
         assert.equal(opts.naturalSearch, true);
         assert.equal(opts.helpOnEmptyStrings, true);
         assert.equal(opts.matcher(), true);

frontend_tests/node_tests/search_legacy.js

@@ -63,9 +63,10 @@ run_test('initialize', () => {
         assert(search.is_using_input_method);
     };
 
+    search_suggestion.max_num_of_search_results = 999;
     search_query_box.typeahead = (opts) => {
         assert.equal(opts.fixed, true);
-        assert.equal(opts.items, 12);
+        assert.equal(opts.items, 999);
         assert.equal(opts.naturalSearch, true);
         assert.equal(opts.helpOnEmptyStrings, true);
         assert.equal(opts.matcher(), true);

frontend_tests/node_tests/search_suggestion_legacy.js

@@ -13,6 +13,8 @@ zrequire('unread');
 zrequire('common');
 const search = zrequire('search_suggestion');
 
+search.max_num_of_search_results = 15;
+
 const bob = {
     email: 'bob@zulip.com',
     full_name: 'Bob Roberts',

frontend_tests/node_tests/ui_init.js

@@ -99,6 +99,7 @@ zrequire('upload');
 zrequire('compose');
 zrequire('composebox_typeahead');
 zrequire('narrow');
+zrequire('search_suggestion');
 zrequire('search');
 zrequire('tutorial');
 zrequire('notifications');

static/js/search.js

@@ -81,7 +81,7 @@ exports.initialize = function () {
             return suggestions.strings;
         },
         fixed: true,
-        items: 12,
+        items: search_suggestion.max_num_of_search_results,
         helpOnEmptyStrings: true,
         naturalSearch: true,
         highlighter: function (item) {

static/js/search_suggestion.js

@@ -1,3 +1,5 @@
+exports.max_num_of_search_results = 12;
+
 function stream_matches_query(stream_name, q) {
     return common.phrase_match(q, stream_name);
 }
@@ -779,14 +781,21 @@ exports.get_search_result_legacy = function (query) {
         get_has_filter_suggestions,
     ];
 
+    const max_items = exports.max_num_of_search_results;
+
     _.each(filterers, function (filterer) {
+        if (attacher.result.length < max_items) {
             const suggestions = filterer(last, base_operators);
             attacher.attach_many(suggestions);
+        }
     });
 
+    if (attacher.result.length < max_items) {
         const subset_suggestions = get_operator_subset_suggestions(operators);
         attacher.concat(subset_suggestions);
-    return attacher.result;
+    }
+
+    return attacher.result.slice(0, max_items);
 };
 
 exports.get_suggestions_legacy = function (query) {