add root scripts and update contribution guide (#750)

README.md

@@ -59,10 +59,14 @@ Since we want the record and replay sides to share a strongly typed data structu
 
 [Typescript handbook](https://www.typescriptlang.org/docs/handbook/declaration-files/introduction.html)
 
-1. Fork the rrweb component repository you want to patch.
-2. Run `yarn install` to install required dependencies.
-3. Patch the code and pass all the tests.
-4. Push the code and create a pull request.
+1. Fork this repository.
+2. Run `yarn install` in the root to install required dependencies for all sub-packages (note: `npm install` is _not_ recommended).
+3. Run `yarn dev` in the root to get auto-building for all the sub-packages whenever you modify anything.
+4. Navigate to one of the sub-packages (in the `packages` folder) where you'd like to make a change.
+5. Patch the code and run `yarn test` to run the tests, make sure they pass before you commit anything.
+6. Push the code and create a pull request.
+
+Protip: You can run `yarn test` in the root folder to run all the tests.
 
 In addition to adding integration tests and unit tests, rrweb also provides a REPL testing tool.
 

package.json

@@ -24,6 +24,10 @@
   },
   "scripts": {
     "lerna": "lerna",
+    "build:all": "yarn lerna run prepublish",
+    "test": "yarn lerna run test",
+    "test:watch": "yarn lerna run test:watch --parallel",
+    "dev": "yarn lerna run dev --parallel",
     "repl": "cd packages/rrweb && npm run repl"
   }
 }

packages/rrweb-snapshot/package.json

@@ -6,8 +6,10 @@
     "prepare": "npm run prepack",
     "prepack": "npm run bundle && npm run typings",
     "test": "jest",
+    "test:watch": "jest --watch",
     "bundle": "rollup --config",
     "bundle:es-only": "cross-env ES_ONLY=true rollup --config",
+    "dev": "yarn bundle:es-only --watch",
     "typings": "tsc -d --declarationDir typings",
     "prepublish": "npm run typings && npm run bundle"
   },

packages/rrweb/package.json

@@ -9,6 +9,7 @@
     "test:headless": "npm run bundle:browser && PUPPETEER_HEADLESS=true jest",
     "test:watch": "PUPPETEER_HEADLESS=true npm run test -- --watch",
     "repl": "npm run bundle:browser && node scripts/repl.js",
+    "dev": "yarn bundle:browser --watch",
     "bundle:browser": "cross-env BROWSER_ONLY=true rollup --config",
     "bundle": "rollup --config",
     "typings": "tsc -d --declarationDir typings",