chore: update circle ci config to use re-useable commands (#424)

* chore: update circle ci config to use re-useable commands.

* squash: add branch filters

.circleci/config.yml

@@ -2,55 +2,53 @@
 #
 # Check https://circleci.com/docs/2.0/language-javascript/ for more details
 #
-version: 2
+version: 2.1
 
-build-common: &common-build
-  working_directory: ~/repo
+commands:
+  test-nodejs:
+    steps:
+      - checkout
+      # Download and cache dependencies
+      - restore_cache:
+          keys:
+            - v1-dependencies-{{ checksum "package.json" }}
+            # fallback to using the latest cache if no exact match is found
+            - v1-dependencies-
 
-  steps:
-    - checkout
+      - run: npm install
 
-    # Download and cache dependencies
-    - restore_cache:
-        keys:
-          - v1-dependencies-{{ checksum "package.json" }}
-          # fallback to using the latest cache if no exact match is found
-          - v1-dependencies-
+      - save_cache:
+          paths:
+            - node_modules
+          key: v1-dependencies-{{ checksum "package.json" }}
 
-    - run: npm install
-
-    - save_cache:
-        paths:
-          - node_modules
-        key: v1-dependencies-{{ checksum "package.json" }}
-
-    # run tests!
-    - run: npm run ci
+      # run tests!
+      - run: npm run ci
 
 jobs:
   node10:
     docker:
       - image: circleci/node:10
-    <<: *common-build
-
-    filters:
-      branches:
-        ignore:
-          - gh-pages
+    steps:
+      - test-nodejs
 
   node12:
     docker:
       - image: circleci/node:12
-    <<: *common-build
-
-    filters:
-      branches:
-        ignore:
-          - gh-pages
+    steps:
+      - test-nodejs
 
 workflows:
   version: 2
   test_node_versions:
     jobs:
-      - node10
-      - node12
+      - node10:
+        filters:
+          branches:
+            ignore:
+              - gh-pages
+      - node12:
+        filters:
+          branches:
+            ignore:
+              - gh-pages