From 5fb33fd194e76fbf7ff06d0a52496b53acb50f89 Mon Sep 17 00:00:00 2001
From: Sergey Kintsel <sergey.kintsel@toptal.com>
Date: Tue, 17 May 2016 21:30:36 +0700
Subject: [PATCH] Add Query#exists? method that bases on :count search_type

---
 lib/chewy/query.rb       |  8 ++++++++
 spec/chewy/query_spec.rb | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/lib/chewy/query.rb b/lib/chewy/query.rb
index cc93d65a8..2d3aeb757 100644
--- a/lib/chewy/query.rb
+++ b/lib/chewy/query.rb
@@ -953,6 +953,14 @@ def find *ids
       ids.one? && !ids.first.is_a?(Array) ? results.first : results
     end
 
+    # Returns true if there are at least one document that matches the query
+    #
+    #   PlacesIndex.query(...).filter(...).exists?
+    #
+    def exists?
+      search_type(:count).total > 0
+    end
+
     # Returns request total time elapsed as reported by elasticsearch
     #
     #   UsersIndex.query(...).filter(...).took
diff --git a/spec/chewy/query_spec.rb b/spec/chewy/query_spec.rb
index e97d36ac4..408eb4306 100644
--- a/spec/chewy/query_spec.rb
+++ b/spec/chewy/query_spec.rb
@@ -452,6 +452,17 @@
     specify { expect { subject.find([10, 20]) }.to raise_error Chewy::DocumentNotFound }
   end
 
+  describe '#exists?' do
+    let(:data) { 10.times.map { |i| {id: i.next.to_s, name: "Name#{i.next}", age: 10 * i.next}.stringify_keys! } }
+
+    before { ProductsIndex::Product.import!(data.map { |h| double(h) }) }
+
+    specify { expect(subject.exists?).to eq true }
+    specify { expect(subject.limit(5).exists?).to eq true }
+    specify { expect(subject.filter(range: {age: {gt: 20}}).limit(3).exists?).to eq true }
+    specify { expect(subject.filter(range: {age: {lt: 0}}).exists?).to eq false }
+  end
+
   describe '#none' do
     specify { expect(subject.none).to be_a described_class }
     specify { expect(subject.none).not_to eq(subject) }