Prettier spike

.prettierrc

@@ -0,0 +1,4 @@
+{
+    "singleQuote": true
+}
+

build/ci/templates/build_compile_jobs.yml

@@ -17,3 +17,11 @@ jobs:
     vmImage: "macos-latest"
   steps:
     - template: build_compile_steps.yml
+
+- job: Prettier
+  variables:
+    build: false
+  pool:
+    vmImage: "macos-latest"
+  steps:
+    - template: prettier_format.yml

build/ci/templates/prettier_format.yml

@@ -0,0 +1,27 @@
+steps:
+    - task: NodeTool@0
+      displayName: "Use Node $(NodeVersion)"
+      inputs:
+          versionSpec: $(NodeVersion)
+
+    - task: Npm@1
+      displayName: "Use NPM $(NpmVersion)"
+      inputs:
+          command: custom
+          verbose: true
+          customCommand: "install -g npm@$(NpmVersion)"
+
+    - task: Npm@1
+      displayName: "npm ci"
+      inputs:
+          command: custom
+          verbose: true
+          customCommand: ci
+  # Check if all files are properly formatted
+  #
+  # Example command line (windows pwsh):
+  # > npm run prettier:check
+    - bash: |
+        npm run prettier:check
+      displayName: "Prettier formatting check"
+      failOnStderr: true

package.json

@@ -2215,6 +2215,8 @@
         "dump-datascience-webpack-stats": "npx -n --max_old_space_size=4096 webpack --config webpack.datascience-ui.config.js --profile --json > tmp/ds-stats.json",
         "compile-webviews": "gulp compile-webviews",
         "compile-webviews-verbose": "npx webpack --config webpack.datascience-ui.config.js",
+        "prettier:format": "prettier --write '{src,uitests}/**/*.{ts,tsx,js,css}'",
+        "prettier:check": "prettier --check '{src,uitests}/**/*.{ts,tsx,js,css}'",
         "postinstall": "node ./node_modules/vscode/bin/install && node ./build/ci/postInstall.js",
         "test": "node ./out/test/standardTest.js && node ./out/test/multiRootTest.js",
         "test:unittests": "mocha --opts ./build/.mocha.unittests.js.opts",
@@ -2411,6 +2413,7 @@
         "node-has-native-dependencies": "^1.0.2",
         "node-html-parser": "^1.1.13",
         "nyc": "^14.1.1",
+        "prettier": "^1.18.2",
         "raw-loader": "^0.5.1",
         "react": "^16.5.2",
         "react-data-grid": "^6.0.2-0",