Switch package manager from yarn to npm

.circleci/config.yml

@@ -16,34 +16,27 @@ commands:
       postinstall:
         type: steps
         default: []
-      yarn:
-        type: string
-        default: '^1.22.5'
     steps:
-      - run:
-          name: Upgrade yarn for current user
-          command: cd ~ && yarn policies set-version << parameters.yarn >>
-
       - restore_cache:
           keys:
-            - v2.2-dependencies-{{ .Environment.CI_CACHE_KEY }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "yarn.lock" }}-{{ .Branch }}
-            - v2.2-dependencies-{{ .Environment.CI_CACHE_KEY }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "yarn.lock" }}-
-            - v2.2-dependencies-{{ .Environment.CI_CACHE_KEY }}-{{ .Environment.CIRCLE_JOB }}-
+            - v2.3-dependencies-{{ .Environment.CI_CACHE_KEY }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "package-lock.json" }}-{{ .Branch }}
+            - v2.3-dependencies-{{ .Environment.CI_CACHE_KEY }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "package-lock.json" }}-
+            - v2.3-dependencies-{{ .Environment.CI_CACHE_KEY }}-{{ .Environment.CIRCLE_JOB }}-
 
-      - run: yarn install
+      - run: npm ci
       - steps: << parameters.postinstall >>
 
       - save_cache:
-          key: v2.2-dependencies-{{ .Environment.CI_CACHE_KEY }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "yarn.lock" }}-{{ .Branch }}
+          key: v2.3-dependencies-{{ .Environment.CI_CACHE_KEY }}-{{ .Environment.CIRCLE_JOB }}-{{ checksum "package-lock.json" }}-{{ .Branch }}
           paths:
-            - ~/.cache/yarn
+            - ~/.npm
 
   audit:
     steps:
       - checkout
       - install:
           postinstall:
-            - run: yarn audit
+            - run: npm audit
 
   test:
     steps:
@@ -54,27 +47,27 @@ commands:
 
       - run:
           name: Prettier formatting
-          command: yarn check:format
+          command: npm run check:format
 
       - run:
           name: TypeScript type checking
-          command: yarn check:ts
+          command: npm run check:ts
 
       - run:
           name: ESLint
-          command: yarn lint:js
+          command: npm run lint:js
 
       - run:
           name: stylelint
-          command: yarn lint:css
+          command: npm run lint:css
 
       - run:
           name: Jest
-          command: yarn test:unit:coverage --ci --maxWorkers=2 --reporters=default --reporters=jest-junit
+          command: npm run test:unit:coverage -- --ci --maxWorkers=2 --reporters=default --reporters=jest-junit
           environment:
             JEST_JUNIT_OUTPUT_DIR: tmp/test-results
 
-      - run: yarn codecov
+      - run: npx codecov
 
       - store_test_results:
           path: tmp/test-results

.github/CONTRIBUTING.md

@@ -4,38 +4,51 @@ Thank you for taking the time to read how to contribute to Marp for VS Code! Thi
 
 We are following [**the contributing guideline of Marp team projects**](https://github.com/marp-team/.github/blob/master/CONTRIBUTING.md). _You have to read this before starting work._
 
+## Setup repository
+
+The most important difference of Marp for VS Code from common Marp team packages is **using npm package manager instead of yarn**.
+
+```bash
+git clone https://github.com/marp-team/marp-vscode.git
+cd ./marp-vscode
+
+npm install
+```
+
+We had met the trouble of VSIX packaging with yarn many times. [An opened issue in vscode-vsce](https://github.com/microsoft/vscode-vsce/issues/432) is not so received attentions from developers in spite of that many extension authors are using yarn.
+
+Thus, using `npm` is the safest way to develop stable VS Code extension continuously for now.
+
 ## Development
 
 Typically using VS Code's debugger is good. See launch configurations on [`.vscode/launch.json`](../.vscode/launch.json)
 
 ### Launch configurations
 
 - **Build and run**: Compile TypeScript and run compiled extension.
-- **Run**: Only run compiled extension. It's useful running together with `yarn watch`. Recommend to execute `Restart Debugging` manually when updated source code.
+- **Run**: Only run compiled extension. It's useful running together with `npm run watch`. Recommend to execute `Restart Debugging` manually when updated source code.
 - **Run with extensions**: Run compiled extension with enabled other installed extensions. It's useful to validate the race condition.
 
 ### Unit testing
 
-Marp team adopts [Jest](https://jestjs.io/) as test runner. This repository can run unit test by `yarn test:unit`.
+Marp team adopts [Jest](https://jestjs.io/) as test runner. This repository can run unit test by `npm run test:unit`.
 
 ```bash
-yarn test:unit
+npm run test:unit
 ```
 
 > _NOTE:_ It seems to be difficult to run VSCode's E2E test on Jest. We're welcome to contribute for supporting E2E tests.
 
 ### Package VSIX
 
 ```bash
-yarn package
+npm run package
 ```
 
-> _NOTE:_ Packaging tasks will run `vsce` via `npx` to avoid some troubles while bundling. (e.g. [#35](https://github.com/marp-team/marp-vscode/pull/35), [#57](https://github.com/marp-team/marp-vscode/issues/57))
-
 ## Release
 
 ### Publish to Visual Studio Marketplace (_For maintainer_)
 
 A way to release is different from other projects of Marp Team targeted to npm.
 
-Just run `yarn vsce:publish [major|minor|patch]` at the latest `master` branch. It can [bump version](https://github.com/marp-team/.github/blob/master/CONTRIBUTING.md#bump-version) and release to Marketplace at once. Don't forget `git push && git push --tags`!
+Just run `npm run vsce:publish [major|minor|patch]` at the latest `master` branch. It can [bump version](https://github.com/marp-team/.github/blob/master/CONTRIBUTING.md#bump-version) and release to Marketplace at once. Don't forget `git push && git push --tags`!