build: copy from node_modules using NPM postinstall hook, not Paver (RE-MERGE)

Re-merge of 4b64d8342d

The commit after this one contains the fix for the issue that led to the
revert.

scripts/copy-node-modules.sh

@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+# Copy certain npm-installed assets from node_modules to other folders in
+# edx-platform. These assets are used by certain especially-old legacy LMS & CMS
+# frontends that are not set up to import from node_modules directly.
+# Many of the destination folders are named "vendor", because they originally
+# held vendored-in (directly-committed) libraries; once we moved most frontends
+# to use NPM, we decided to keep library versions in-sync by copying to the
+# former "vendor" directories.
+
+# Enable stricter error handling.
+set -euo pipefail
+
+COL_LOG="\e[36m"  # Log/step/section color (cyan)
+COL_OFF="\e[0m"   # Normal color
+
+# Keep these as variables in case we ever want to parameterize this script's
+# input or output dirs, as proposed in:
+# https://github.com/openedx/wg-developer-experience/issues/150
+# https://github.com/openedx/wg-developer-experience/issues/151
+node_modules="node_modules"
+vendor_js="common/static/common/js/vendor"
+vendor_css="common/static/common/css/vendor"
+
+# Stylized logging.
+log ( ) {
+	echo -e "${COL_LOG}$* $COL_OFF"
+}
+
+log "====================================================================================="
+log "Copying required assets from node_modules..."
+log "-------------------------------------------------------------------------------"
+
+# Start echoing all commands back to user for ease of debugging.
+set -x
+
+log "Ensuring vendor directories exist..."
+mkdir -p "$vendor_js"
+mkdir -p "$vendor_css"
+
+log "Copying studio-frontend JS & CSS from node_modules into vendor directores..."
+while read -r -d $'\0' src_file ; do
+    if [[ "$src_file" = *.css ]] || [[ "$src_file" = *.css.map ]] ; then
+        cp --force "$src_file" "$vendor_css"
+    else
+        cp --force "$src_file" "$vendor_js"
+    fi
+done < <(find "$node_modules/@edx/studio-frontend/dist" -type f -print0)
+
+log "Copying certain JS modules from node_modules into vendor directory..."
+cp --force \
+    "$node_modules/backbone.paginator/lib/backbone.paginator.js" \
+    "$node_modules/backbone/backbone.js" \
+    "$node_modules/bootstrap/dist/js/bootstrap.bundle.js" \
+    "$node_modules/hls.js/dist/hls.js" \
+    "$node_modules/jquery-migrate/dist/jquery-migrate.js" \
+    "$node_modules/jquery.scrollto/jquery.scrollTo.js" \
+    "$node_modules/jquery/dist/jquery.js" \
+    "$node_modules/moment-timezone/builds/moment-timezone-with-data.js" \
+    "$node_modules/moment/min/moment-with-locales.js" \
+    "$node_modules/picturefill/dist/picturefill.js" \
+    "$node_modules/requirejs/require.js" \
+    "$node_modules/underscore.string/dist/underscore.string.js" \
+    "$node_modules/underscore/underscore.js" \
+    "$node_modules/which-country/index.js" \
+    "$vendor_js"
+
+log "Copying certain JS developer modules into vendor directory..."
+if [[ "${NODE_ENV:-production}" = development ]] ; then
+    cp --force "$node_modules/sinon/pkg/sinon.js" "$vendor_js"
+    cp --force "$node_modules/squirejs/src/Squire.js" "$vendor_js"
+else
+    # TODO: https://github.com/openedx/edx-platform/issues/31768
+    # In the old implementation of this scipt (pavelib/assets.py), these two
+    # developer libraries were copied into the JS vendor directory whether not
+    # the build was for prod or dev. In order to exactly match the output of
+    # the old script, this script will also copy them in for prod builds.
+    # However, in the future, it would be good to only copy them for dev
+    # builds. Furthermore, these libraries should not be `npm install`ed
+    # into prod builds in the first place.
+    cp --force "$node_modules/sinon/pkg/sinon.js" "$vendor_js" || true      # "|| true" means "tolerate errors"; in this case,
+    cp --force "$node_modules/squirejs/src/Squire.js" "$vendor_js" || true  # that's "tolerate if these files don't exist."
+fi
+
+# Done echoing.
+set +x
+
+log "-------------------------------------------------------------------------------"
+log " Done copying required assets from node_modules."
+log "====================================================================================="
+