Fix/api size (#20819)

* config: don't transpile the lib files

* lib: don't mutate the data objects we use to instantiate Member

This has cost me a day of work but it is incredibly simple: because we
initialize our Beta::Member class with the Jekyll::Document hash, it
means doing

1. @startups = value from the hash
2. def active_startups; @startups.concat(...); end

means we're actually modifying the value from the hash since it's just
a reference being passed around. Jekyll maintains that `doc.data`
reference to build up the template but that references keeps growing
with every call to the methods `active_startups` or `legacy_startup`.

My bad! I thought `Array#concat` returned a new array...

_config.yml

@@ -39,7 +39,7 @@ exclude: [
   "content/templates",
   "README.md",
   "CONTRIBUTING.md",
-  "rb",
+  "lib",
   "vendor",
   "ci",
   "Gemfile",

lib/models/member.rb

@@ -43,20 +43,17 @@ def legacy_missions
     end
 
     def active_startups
-      startups.concat(
-        active_missions
-          .map { |mission| mission['startups'] }
-          .flatten
+      (
+        startups +
+        active_missions.map { |mission| mission['startups'] }.flatten
       ).uniq
     end
 
     def legacy_startups
-      previously.concat(
-        legacy_missions
-          .map { |mission| mission['startups'] }
-          .flatten
+      (
+        previously +
+        legacy_missions.map { |mission| mission['startups'] }.flatten
       ).uniq
     end
-
   end
 end

spec/lib/models/member_spec.rb

@@ -33,42 +33,54 @@
     end
   end
 
-  context "when the member has an active mission" do
-    before { data['missions'][0]['end'] = Date.current.tomorrow }
+  describe "#active_missions" do
+    context "when the member has an active mission" do
+      before { data['missions'][0]['end'] = Date.current.tomorrow }
 
-    it "is included in active_missions" do
-      expect(member.active_missions).to include data["missions"].first
-    end
+      it "is included in active_missions" do
+        expect(member.active_missions).to include data["missions"].first
+      end
+
+      it "includes its startups in active_startups" do
+        expect(member.active_startups).to include "aplypro"
+      end
 
-    it "includes its startups in active_startups" do
-      expect(member.active_startups).to include "aplypro"
+      it "does not modify the original variable" do
+        expect { member.active_startups }.not_to change(member.startups, :count)
+      end
     end
   end
 
-  context "when the member has an inactive mission" do
-    before { data['missions'][0]['end'] = Date.new(2000, 1, 1) }
+  describe "#legacy_startups" do
+    context "when the member has an inactive mission" do
+      before { data['missions'][0]['end'] = Date.new(2000, 1, 1) }
 
-    it "is not included in active missions" do
-      expect(member.active_missions).to be_empty
-    end
+      it "is not included in active missions" do
+        expect(member.active_missions).to be_empty
+      end
 
-    it "is included in the legacy_startups" do
-      expect(member.legacy_startups).to include "aplypro"
-    end
-  end
+      it "is included in the legacy_startups" do
+        expect(member.legacy_startups).to include "aplypro"
+      end
 
-  context "when there are legacy-syntax startups" do
-    before do
-      data["startups"] = ["foo", "bar"]
-      data["previously"] = ["bat", "man"]
+      it "does not modify the original variable" do
+        expect { member.legacy_startups }.not_to change(member.previously, :count)
+      end
     end
 
-    it "merges them in active_startups" do
-      expect(member.active_startups).to contain_exactly *["aplypro", "foo", "bar"]
-    end
+    context  "when there are legacy-syntax startups" do
+      before do
+        data["startups"] = ["foo", "bar"]
+        data["previously"] = ["bat", "man"]
+      end
+
+      it "merges them in active_startups" do
+        expect(member.active_startups).to contain_exactly *["aplypro", "foo", "bar"]
+      end
 
-    it "merges them in legacy_startups" do
-      expect(member.legacy_startups).to contain_exactly *["bat", "man"]
+      it "merges them in legacy_startups" do
+        expect(member.legacy_startups).to contain_exactly *["bat", "man"]
+      end
     end
   end
 end