feat: play around with dependency versions

.editorconfig

@@ -0,0 +1,12 @@
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+end_of_line = lf
+insert_final_newline = true
+
+[*.{js,json,ts,md}]
+charset = utf-8
+indent_style = space
+indent_size = 2

README.md

@@ -2,7 +2,6 @@
 
 yarn 0.27.x introduced the [yarn workspaces feature][1].
 
-[1]: https://github.com/yarnpkg/yarn/issues/3294
 
 
 
@@ -32,3 +31,129 @@ error The workspace feature is currently experimental and needs to be manually e
 The cool thing is that workspaces can be enabled only for a specific project.
 Adding `.yarnrc` to the project root and simply add the above line to it!
 
+
+## Building a multi-package Angular project
+
+Let's now try to build a multi-package Angular project inspired by the project layout of [angular/angular][3]
+
+
+```
+demo
+  |- .angular-cli.json
+  |- package.json
+packages
+  |- common
+       |- package.json
+  |- components
+       |- package.json
+```
+
+Then, we must give workspaces name and at least add the `name` property to the `package.json` files!
+
+Example `packages/common/package.json`:
+
+```json
+{
+  "name": "@foo/common",
+  "version": "1.0.0",
+  "private": true
+}
+```
+
+Running commands in a single workspace:
+
+```bash
+$ yarn workspace @foo/common add @angular/common
+$ yarn workspace @foo/components add @angular/http
+```
+
+What happened?
+
+Yarn installs dependencies to the project's root folder, e.g. `node_modules/@angular`.
+By node's module resolution algorithm, sub-projects will recursively walk up the file-tree until they find a `node_modules` folder with the right dependencies!
+
+A little bit counter-intuitive, this does not add the dependencies to the sub-projects but rather to the top-level `package.json`!
+
+Also, it creates symlinks from the top-level `node_modules/@foo` folder to the directories of the individual workspaces:
+
+```bash
+$ ls -l node_modules/@foo
+total 24
+lrwxr-xr-x  ...  common -> ../../packages/common
+lrwxr-xr-x  ...  components -> ../../packages/components
+lrwxr-xr-x  ...  demo-app -> ../../demo
+```
+
+What happens on dependency version conflicts?
+
+Let's simulate that by adding to `demo/package.json`:
+
+```json
+{
+  "name": "@foo/demo-app",
+  "version": "1.0.0",
+  "private": true,
+  "dependencies": {
+    "@angular/core": "4.2.0",
+    "@angular/common": "4.2.0",
+    "@angular/http": "4.2.0",
+    "@angular/platform-browser": "4.2.0"
+  }
+}
+```
+
+```bash
+$ rm yarn.lock
+$ yarn install
+yarn install v0.27.5
+info No lockfile found.
+[1/4] Resolving packages...
+[2/4] Fetching packages...
+[3/4] Linking dependencies...
+[4/4] Building fresh packages...
+success Saved lockfile.
+Done in 2.32s.
+$ cat node_modules/@angular/http/package.json
+{
+  "name": "@angular/http",
+  "version": "4.3.1",
+  "description": "Angular - the http service",
+  "main": "./bundles/http.umd.js",
+  ...
+}
+```
+
+Uh, the install command silently installed the `4.3.1` version, even though `@foo/demo` specified the `4.2.0` version.
+But wait, there's another `demo/node_modules` directory created now!
+
+```bash
+$ cat demo/node_modules/@angular/http/package.json
+{
+  "name": "@angular/http",
+  "version": "4.2.0",
+  "description": "Angular - the http service",
+  "main": "./bundles/http.umd.js",
+  ...
+}
+```
+
+That means that `yarn install` installs local dependencies, if needed, next to the `package.json` of the workspace.
+It tries to assemble global depencies of all worksapces next to the root-level `package.json`!
+
+I suggest that working on different Angular versions within the same project isn't a very good idea.
+So, when we change everything to depend on the `4.3.1` version and re-run:
+
+```bash
+$ rm -rf demo/node_modules
+$ rm -rf node_modules
+$ rm yarn.lock
+$ yarn install
+```
+
+Now, we only get dependencies installed to the top-most `node_modules` directory, meaning that all workspaces share the same depencies!
+
+
+
+[1]: https://github.com/yarnpkg/yarn/issues/3294
+[2]: https://github.com/thejameskyle/rfcs-1/blob/workspaces/accepted/0000-workspaces.md
+[3]: https://github.com/angular/angular

demo/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "@foo/demo-app",
+  "version": "1.0.0",
+  "private": true,
+  "dependencies": {
+    "@angular/core": "4.3.1",
+    "@angular/common": "4.3.1",
+    "@angular/http": "4.3.1",
+    "@angular/platform-browser": "4.3.1"
+  }
+}

package.json

@@ -7,6 +7,13 @@
   "author": "David <david@spektrakel.de>",
   "license": "MIT",
   "workspaces": [
-
-  ]
+    "packages/*",
+    "demo"
+  ],
+  "dependencies": {
+    "@angular/http": "^4.3.1",
+    "@angular/platform-browser": "^4.3.1",
+    "rxjs": "^5.4.2",
+    "zone.js": "^0.8.14"
+  }
 }

packages/common/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "@foo/common",
+  "version": "1.0.0",
+  "private": true,
+  "peerDependencies": {
+    "@angular/common": "4.3.1",
+    "@angular/http": "4.3.1"
+  }
+}

packages/components/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "@foo/components",
+  "version": "1.0.0",
+  "private": true,
+  "peerDependencies": {
+    "@angular/common": "4.3.1"
+  }
+}

yarn.lock

@@ -2,3 +2,44 @@
 # yarn lockfile v1
 
 
+"@angular/common@4.3.1":
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/@angular/common/-/common-4.3.1.tgz#260f487a7cdca326c436bd3ea9515c797de2ff72"
+  dependencies:
+    tslib "^1.7.1"
+
+"@angular/core@4.3.1":
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/@angular/core/-/core-4.3.1.tgz#a9d0a7d644b96260674269b689a04feea632a8d3"
+  dependencies:
+    tslib "^1.7.1"
+
+"@angular/http@4.3.1", "@angular/http@^4.3.1":
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/@angular/http/-/http-4.3.1.tgz#e4f661f746711e88ecbea76a3c905babf97d315a"
+  dependencies:
+    tslib "^1.7.1"
+
+"@angular/platform-browser@4.3.1", "@angular/platform-browser@^4.3.1":
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/@angular/platform-browser/-/platform-browser-4.3.1.tgz#db727b06eed64bda5defec71815db26a4da2f690"
+  dependencies:
+    tslib "^1.7.1"
+
+rxjs@^5.4.2:
+  version "5.4.2"
+  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-5.4.2.tgz#2a3236fcbf03df57bae06fd6972fd99e5c08fcf7"
+  dependencies:
+    symbol-observable "^1.0.1"
+
+symbol-observable@^1.0.1:
+  version "1.0.4"
+  resolved "https://registry.yarnpkg.com/symbol-observable/-/symbol-observable-1.0.4.tgz#29bf615d4aa7121bdd898b22d4b3f9bc4e2aa03d"
+
+tslib@^1.7.1:
+  version "1.7.1"
+  resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.7.1.tgz#bc8004164691923a79fe8378bbeb3da2017538ec"
+
+zone.js@^0.8.14:
+  version "0.8.14"
+  resolved "https://registry.yarnpkg.com/zone.js/-/zone.js-0.8.14.tgz#0c4db24b178232274ccb43f78c99db7f3642b6cf"