Update publish to NPM script (#96)

* update publish script

* bump version

Author: nikrom17

scripts/publish.sh

@@ -1,4 +1,22 @@
 #!/bin/sh
 
-# Running `npm version` will run through the other version lifecycle scripts
-npm version ${1-patch};
+# This script will determine the type of release based on the git branch.
+# When the default branch is used, it will be a `patch` that's published to npm
+# under the `latest` dist-tag. Any other branch will be a `prelease` that's
+# published to npm under the `alpha-$SHA` dist-tag.
+bump='patch'
+tag='latest'
+
+current_branch=$(git rev-parse --abbrev-ref HEAD)
+default_branch=$(git remote show origin | sed -n '/HEAD branch/s/.*: //p')
+current_sha=$(git rev-parse --short HEAD)
+
+if [ "$current_branch" != "$default_branch" ]; then
+  bump='prerelease'
+  tag="alpha-$current_sha"
+  export tag
+  npm --no-git-tag-version version $bump --preid=$tag
+else
+  export tag
+  npm version $bump
+fi