Adds CircleCI configuration (#39)

* Adds initial circle config file

* Add script to checksum all packages package.json, save cache based on this.

* Use yarn with lerna

* remove --no-ci option

* slightly clarify documentation

* Adds lint step

.circleci/checksum.sh

@@ -0,0 +1,26 @@
+#! /bin/sh
+#
+# Usage: checksum.sh filename
+#
+# checksum.sh computes the checksum of the repo's top level `package.json`
+# and `package.json` files in package/, putting the hashes into a file in
+# alphabetical order. Must be run at the top level of the repository.
+
+
+if [ -z $1 ]; then
+    echo "Usage: checksum.sh filename"
+    exit 1
+fi
+
+FILE=$1
+
+# remove existing file
+if [ -f $FILE ]; then
+    rm $FILE
+fi
+
+openssl md5 package.json >> $FILE
+
+find packages/*/package.json | xargs -I{} openssl md5 {} >> $FILE
+
+sort -o $FILE $FILE

.circleci/config.yml

@@ -0,0 +1,33 @@
+version: 2
+
+jobs:
+  build:
+    docker:
+      - image: circleci/node:12
+    steps:
+      - checkout
+      - run:
+          name: Create Checksum
+          command: sh .circleci/checksum.sh /tmp/checksums.txt
+      - restore_cache:
+          keys:
+            - npm-cache-{{ checksum "/tmp/checksums.txt" }}
+      - run:
+          name: Install Dependencies
+          command: yarn install
+      - save_cache:
+          key: npm-cache-{{ checksum "/tmp/checksums.txt" }}
+          paths:
+            - ./node_modules
+            - ./yarn.lock
+            - ./packages/*/node_modules
+            - ./packages/*/yarn.lock
+      - run:
+          name: Lint
+          command: yarn run check
+      - run:
+          name: Compile
+          command: yarn run compile
+      - run:
+          name: Test
+          command: yarn run test

lerna.json

@@ -1,5 +1,6 @@
 {
   "lerna": "3.13.4",
+  "npmClient": "yarn",
   "packages": [
     "packages/*"
   ],