Reorder link and install steps

Take advantage of Yarn's preservation of links while installing and set up links
first and install second. This should result in a small speedup since we no
longer install the published SDKs just to replace them on the next line.

README.md

@@ -137,27 +137,26 @@ choice).
 Using `yarn` instead of `npm` is recommended. Please see the Yarn [install
 guide](https://yarnpkg.com/docs/install/) if you do not have it already.
 
-Then check out the code and pull in dependencies:
-
-```bash
-git clone https://github.com/matrix-org/matrix-react-sdk.git
-cd matrix-react-sdk
-git checkout develop
-yarn install
-```
-
 `matrix-react-sdk` depends on `matrix-js-sdk`. To make use of changes in the
 latter and to ensure tests run against the develop branch of `matrix-js-sdk`,
-you should check out `matrix-js-sdk`, change into that new directory, and run:
+you should set up `matrix-js-sdk`:
 
 ```bash
+git clone https://github.com/matrix-org/matrix-js-sdk
+cd matrix-js-sdk
+git checkout develop
 yarn link
+yarn install
 ```
 
-Then, switch back to `matrix-react-sdk` and run:
+Then check out `matrix-react-sdk` and pull in dependencies:
 
 ```bash
+git clone https://github.com/matrix-org/matrix-react-sdk
+cd matrix-react-sdk
+git checkout develop
 yarn link matrix-js-sdk
+yarn install
 ```
 
 See the [help for `yarn link`](https://yarnpkg.com/docs/cli/link) for more

jenkins.sh

@@ -8,13 +8,17 @@ nvm use 10
 
 set -x
 
-# install the other dependencies
+scripts/fetchdep.sh matrix-org matrix-js-sdk
+
+pushd matrix-js-sdk
+yarn link
 yarn install
+popd
 
-scripts/fetchdep.sh matrix-org matrix-js-sdk
-rm -r node_modules/matrix-js-sdk || true
-ln -s ../matrix-js-sdk node_modules/matrix-js-sdk
-(cd matrix-js-sdk && yarn install)
+yarn link matrix-js-sdk
+
+# install the other dependencies
+yarn install
 
 # run the mocha tests
 yarn test --no-colors

scripts/travis/build.sh

@@ -9,19 +9,17 @@ set -ev
 RIOT_WEB_DIR=riot-web
 REACT_SDK_DIR=`pwd`
 
+yarn link
+
 scripts/fetchdep.sh vector-im riot-web
-pushd "$RIOT_WEB_DIR"
 
-mkdir node_modules
-yarn install
+pushd "$RIOT_WEB_DIR"
 
-# use the version of js-sdk we just used in the react-sdk tests
-rm -r node_modules/matrix-js-sdk
-ln -s "$REACT_SDK_DIR/node_modules/matrix-js-sdk" node_modules/matrix-js-sdk
+yarn link matrix-js-sdk
+yarn link matrix-react-sdk
 
-# ... and, of course, the version of react-sdk we just built
-rm -r node_modules/matrix-react-sdk
-ln -s "$REACT_SDK_DIR" node_modules/matrix-react-sdk
+yarn install
 
 yarn build
+
 popd

scripts/travis/install-deps.sh

@@ -1,11 +1,12 @@
 #!/bin/sh
 
 set -ex
-yarn install
+
 scripts/fetchdep.sh matrix-org matrix-js-sdk
-rm -r node_modules/matrix-js-sdk || true
-ln -s ../matrix-js-sdk node_modules/matrix-js-sdk
 
-cd matrix-js-sdk
+pushd matrix-js-sdk
+yarn link
 yarn install
-cd ..
+popd
+
+yarn link matrix-js-sdk