install step 3

.circleci/config.yml

@@ -4,5 +4,12 @@ jobs:
     docker: &docker
       - image: circleci/node:12
     steps:
-      - checkout # check out the code in the project directory
-      - run: echo "hello world" # run the `echo` command
+      - checkout
+      - restore_cache:
+          keys:
+            - npm-v1-dependencies-{{ checksum "yarn.lock" }}
+      - run: yarn global add node-gyp && yarn install
+      - save_cache:
+          paths:
+            - ./node_modules
+          key: npm-v1-dependencies-{{ checksum "yarn.lock" }}