use yarn instead of npm

Author: ianhi

.github/workflows/build.yml

@@ -56,7 +56,7 @@ jobs:
         cookiecutter . --config-file tests/testconfig.yaml --no-input
         pushd jupyter-widget-testwidgets
         python -m pip install --upgrade -v -e ".[test, examples, docs]"
-        npm run lint:check
+        yarn run lint:check
 
         # TODO: re-enable tests
         # pytest

README.md

@@ -47,15 +47,15 @@ pip install -e ".[test, examples]"
 py.test
 
 # Run the JS tests. This should again, only give TODO errors (Expected 'Value' to equal 'Expected value'):
-npm test
+yarn test
 ```
 
 When developing your extensions, you need to manually enable your extensions with the
 notebook / lab frontend. For lab, this is done by the command:
 
 ```
 jupyter labextension develop --overwrite .
-npm run build
+yarn run build
 ```
 
 For classic notebook, you can run:
@@ -78,7 +78,7 @@ terminals to watch for changes in the extension's source and automatically rebui
 
 ```bash
 # Watch the source directory in one terminal, automatically rebuilding when needed
-npm run watch
+yarn run watch
 # Run JupyterLab in another terminal
 jupyter lab
 ```

{{cookiecutter.github_project_name}}/.github/workflows/build.yml

@@ -49,9 +49,9 @@ jobs:
     - name: Test the extension
       run: |
         python -m pip install --upgrade -v -e ".[test, examples, docs]"
-        npm run lint:check
+        yarn run lint:check
         pytest
-        npm run test:ci
+        yarn run test:ci
     - name: Check docs can be build + links
       run: |
         pushd docs

{{cookiecutter.github_project_name}}/README.md

@@ -34,7 +34,7 @@ notebook / lab frontend. For lab, this is done by the command:
 
 ```
 jupyter labextension develop --overwrite .
-npm run build
+yarn run build
 ```
 
 For classic notebook, you need to run:
@@ -56,7 +56,7 @@ terminals to watch for changes in the extension's source and automatically rebui
 
 ```bash
 # Watch the source directory in one terminal, automatically rebuilding when needed
-npm run watch
+yarn run watch
 # Run JupyterLab in another terminal
 jupyter lab
 ```

{{cookiecutter.github_project_name}}/package.json

@@ -29,20 +29,20 @@
     "url": "https://github.com/{{ cookiecutter.github_organization_name }}/{{ cookiecutter.github_project_name }}"
   },
   "scripts": {
-    "build": "npm run build:lib && npm run build:nbextension && npm run build:labextension:dev",
-    "build:prod": "npm run build:lib && npm run build:nbextension && npm run build:labextension",
+    "build": "yarn run build:lib && yarn run build:nbextension && yarn run build:labextension:dev",
+    "build:prod": "yarn run build:lib && yarn run build:nbextension && yarn run build:labextension",
     "build:labextension": "jupyter labextension build .",
     "build:labextension:dev": "jupyter labextension build --development True .",
     "build:lib": "tsc",
     "build:nbextension": "webpack",
-    "clean": "npm run clean:lib && npm run clean:nbextension && npm run clean:labextension",
+    "clean": "yarn run clean:lib && yarn run clean:nbextension && yarn run clean:labextension",
     "clean:lib": "rimraf lib",
     "clean:labextension": "rimraf {{ cookiecutter.python_package_name }}/labextension",
     "clean:nbextension": "rimraf {{ cookiecutter.python_package_name }}/nbextension/static/index.js",
     "lint": "eslint . --ext .ts,.tsx --fix",
     "lint:check": "eslint . --ext .ts,.tsx",
-    "prepack": "npm run build:lib",
-    "test": "npm run test:firefox",
+    "prepack": "yarn run build:lib",
+    "test": "yarn run test:firefox",
     "test:chrome": "karma start --browsers=Chrome tests/karma.conf.js",
     "test:debug": "karma start --browsers=Chrome --singleRun=false --debug=true tests/karma.conf.js",
     "test:firefox": "karma start --browsers=Firefox tests/karma.conf.js",