Move from yarn to npm

.appveyor.yml

@@ -72,8 +72,7 @@ init:
 
 install:
   - ps: Install-Product node $env:nodejs_version
-  - npm i -g yarn
-  - yarn --frozen-lockfile
+  - npm ci
   - "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"
   - python -m pip install -U pip
   - pip install -t ./pythonFiles/experimental/ptvsd git+https://github.com/Microsoft/ptvsd/
@@ -93,17 +92,17 @@ build: off
 #   - "xcopy /S /I c:\\projects\\PTVS\\BuildOutput\\VsCode\\raw analysis"
 
 test_script:
-  - yarn run clean
-  - yarn run vscode:prepublish
+  - npm run clean
+  - npm run vscode:prepublish
   - if [%DEBUGGER_TEST%]==[true] (
-      yarn run testDebugger --silent)
-  - yarn run clean:ptvsd
+      npm run testDebugger --silent)
+  - npm run clean:ptvsd
   - pip install -t ./pythonFiles/experimental/ptvsd ptvsd --pre --no-cache-dir
   - if [%DEBUGGER_TEST_RELEASE%]==[true] (
-      yarn run testDebugger --silent)
+      npm run testDebugger --silent)
   - if [%SINGLE_WORKSPACE_TEST%]==[true] (
-      yarn run testSingleWorkspace --silent)
+      npm run testSingleWorkspace --silent)
   - if [%MULTIROOT_WORKSPACE_TEST%]==[true] (
-      yarn run testMultiWorkspace --silent)
+      npm run testMultiWorkspace --silent)
   # - if [%ANALYSIS_TEST%]==[true] (
-  #     yarn run testAnalysisEngine --silent)
+  #     npm run testAnalysisEngine --silent)

.travis.yml

@@ -65,51 +65,52 @@ before_install: |
   source ./.nvm/nvm.sh
   nvm install 8.9.1
   nvm use 8.9.1
-  yarn global add vsce
-  yarn global add azure-cli
+  npm install npm@latest -g
+  npm install -g vsce
+  npm install -g azure-cli
   export TRAVIS_PYTHON_PATH=`which python`
 install:
   - python -m pip install --upgrade -r requirements.txt
   - python -m pip install -t ./pythonFiles/experimental/ptvsd git+https://github.com/Microsoft/ptvsd/
-  - yarn --frozen-lockfile
+  - npm ci
 
 script:
   - if [ $DEBUGGER_TEST == "true" ]; then
-        yarn run clean;
-        yarn run vscode:prepublish;
-        yarn run cover:enable;
-        yarn run testDebugger --silent;
+        npm run clean;
+        npm run vscode:prepublish;
+        npm run cover:enable;
+        npm run testDebugger --silent;
     fi
-  - yarn run debugger-coverage
+  - npm run debugger-coverage
   - if [ $TRAVIS_UPLOAD_COVERAGE == "true" ]; then
         bash <(curl -s https://codecov.io/bash);
     fi
-  - yarn run clean:ptvsd
+  - npm run clean:ptvsd
   - pip install -t ./pythonFiles/experimental/ptvsd ptvsd --pre --no-cache-dir;
   - if [ $DEBUGGER_TEST_RELEASE == "true" ]; then
-        yarn run clean;
-        yarn run vscode:prepublish;
-        yarn run cover:enable;
-        yarn run testDebugger --silent;
+        npm run clean;
+        npm run vscode:prepublish;
+        npm run cover:enable;
+        npm run testDebugger --silent;
     fi
-  - yarn run debugger-coverage
+  - npm run debugger-coverage
   - if [ $TRAVIS_UPLOAD_COVERAGE == "true" ]; then
         bash <(curl -s https://codecov.io/bash);
     fi
   - if [ $SINGLE_WORKSPACE_TEST == "true" ]; then
-        yarn run clean;
-        yarn run vscode:prepublish;
-        yarn run cover:enable;
-        yarn run testSingleWorkspace --silent;
+        npm run clean;
+        npm run vscode:prepublish;
+        npm run cover:enable;
+        npm run testSingleWorkspace --silent;
     fi
   - if [ $TRAVIS_UPLOAD_COVERAGE == "true" ]; then
         bash <(curl -s https://codecov.io/bash);
     fi
   - if [ $MULTIROOT_WORKSPACE_TEST == "true" ]; then
-        yarn run clean;
-        yarn run vscode:prepublish;
-        yarn run cover:enable;
-        yarn run testMultiWorkspace --silent;
+        npm run clean;
+        npm run vscode:prepublish;
+        npm run cover:enable;
+        npm run testMultiWorkspace --silent;
     fi
   - if [ $TRAVIS_UPLOAD_COVERAGE == "true" ]; then
         bash <(curl -s https://codecov.io/bash);
@@ -124,7 +125,7 @@ script:
         python3 news/announce.py --dry_run;
     fi
   - if [[ $AZURE_STORAGE_ACCOUNT && "$TRAVIS_BRANCH" == "master" && "$TRAVIS_PULL_REQUEST" == "false" ]]; then
-        yarn run clean;
+        npm run clean;
         vsce package;
         azure storage blob upload python*.vsix $AZURE_STORAGE_CONTAINER ms-python-insiders.vsix --account-name $AZURE_STORAGE_ACCOUNT --account-key $AZURE_STORAGE_ACCESS_KEY --quiet;
     fi

CONTRIBUTING.md

@@ -9,7 +9,7 @@
 
 ### Prerequisites
 
-1. Node.js (>= 8.9.1, < 9.0.0), and [Yarn](https://yarnpkg.com/lang/en/docs/install/)
+1. Node.js (>= 8.9.1, < 9.0.0)
 2. Python 2.7 or later (required only for testing the extension and running unit tests)
 3. Windows, macOS, or Linux
 4. Visual Studio Code
@@ -22,7 +22,7 @@
 ```shell
 git clone https://github.com/microsoft/vscode-python
 cd vscode-python
-yarn install --lock-file
+npm install
 ```
 
 You may see warnings that ```The engine "vscode" appears to be invalid.```, you can ignore these.

news/3 Code Health/1402.md

@@ -0,0 +1 @@
+Move from yarn to npm.