Update samples/js/**/README (#1979)

samples/js/README.md

@@ -0,0 +1,27 @@
+# JS Samples
+
+This directory has a `package.json` and a `node_modules directory`. This is so that we do not have
+to do the slow `npm install` in every sample. Instead each sample have no dependencies and the
+dependencies are added to the shared parent directory. If we instead had complete standalone samples
+in every subdirectory it would would mean that we have to have n copies of all the node modules we
+depend on. This takes a long time to install and it takes up a lot of disk space.
+
+## Running a sample
+
+First run `npm install` in this directory, then in the subdirectory.
+
+```
+cd samples/js
+npm install
+cd fs
+npm install
+```
+
+Then to run the sample:
+
+```
+node .
+```
+
+You only need to do the `npm install` calls once. After that you can use `npm run build` or
+`npm run start` for dev mode.

samples/js/bar-chart/README.md

@@ -7,8 +7,10 @@ This renders noms data as a bar chart using Plotly (https://plot.ly/javascript/)
 ## Build
 
 ```
+pushd ..
+npm install
+popd
 npm install
-npm run build
 ```
 
 ## Run

samples/js/counter/README.md

@@ -8,7 +8,12 @@ counter uses noms/js to read and write a simple incrementing counter.
 ```
 noms serve ldb:/tmp/noms &
 cd ../../samples/js/counter
+pushd ..
+npm install
+popd
 npm install
-npm run build
 node . http://localhost:8000:counter
 ```
+
+You only need to do the `npm install` calls once. After that you can use `npm run build` or
+`npm run start` for dev mode.