build: fix populating version placeholder in release builds

Author: vikerman

.bazelrc

@@ -40,7 +40,7 @@ test
 
 # Configures script to do version stamping.
 # See https://docs.bazel.build/versions/master/user-manual.html#flag--workspace_status_command
-build:release --workspace_status_command=./tools/bazel-stamp-vars.sh
+build:release --workspace_status_command="node ./tools/bazel-stamp-vars.js"
 
 ###############################
 # Typescript / Angular / Sass #
@@ -66,4 +66,4 @@ build --define=compile=legacy
 
 # Turn on managed directories feature in Bazel
 # This allows us to avoid installing a second copy of node_modules
-common --experimental_allow_incremental_repository_updates
+common --experimental_allow_incremental_repository_updates

tools/bazel-stamp-vars.js

@@ -0,0 +1,40 @@
+#!/usr/bin/env node
+
+/**
+ * Bazel workspace status script that is responsible for creating Bazel stamping variables.
+ * The stamping variables will be used by the NodeJS Bazel rules to provide proper version
+ * placeholder replacements. Read more about variable stamping within Bazel:
+ * https://docs.bazel.build/versions/master/user-manual.html#flag--workspace_status_command
+ */
+
+const spawnSync = require('child_process').spawnSync;
+const packageJson = require('../package');
+
+const currentCommitSha = getCurrentCommitSha();
+
+// The "BUILD_SCM_VERSION" will be picked up by the "npm_package" and "ng_package"
+// rule in order to populate the "0.0.0-PLACEHOLDER". Note that the SHA will be only
+// appended for snapshots builds from within the "publish-build-artifacts.sh" script.
+console.log(`BUILD_SCM_VERSION ${packageJson.version}`);
+console.log(`BUILD_SCM_COMMIT_SHA ${currentCommitSha}`);
+console.log(`BUILD_SCM_BRANCH ${getCurrentBranchName()}`);
+console.log(`BUILD_SCM_USER ${getCurrentGitUser()}`);
+
+/** Returns the commit SHA for the current git HEAD of the project. */
+function getCurrentCommitSha() {
+  return spawnSync('git', ['rev-parse', 'HEAD']).stdout.toString().trim();
+}
+
+/** Returns the name of the currently checked out branch of the project. */
+function getCurrentBranchName() {
+  return spawnSync('git', ['symbolic-ref', '--short', 'HEAD']).stdout.toString().trim();
+}
+
+/** Returns the name and email of the Git user that creates this release build. */
+function getCurrentGitUser() {
+  const userName = spawnSync('git', ['config', 'user.name']).stdout.toString().trim();
+  const userEmail = spawnSync('git', ['config', 'user.email']).stdout.toString().trim();
+
+  return `${userName} <${userEmail}>`;
+}
+