diff --git a/tools/js-compress.sh b/tools/js-compress.sh
new file mode 100755
index 0000000..60bfa2c
--- /dev/null
+++ b/tools/js-compress.sh
@@ -0,0 +1,75 @@
+#!/bin/bash
+#
+# A development tool that use yuicompressor to compress JS files.
+#
+#
+# Requirement:
+#   - wget
+#   - JRE
+#   - yuicompressor › https://github.com/yui/yuicompressor
+#
+#
+# Usage: bash /path/to/js-compress.sh
+#
+# Process:
+#     input: /path/to/js/source.js --> output: /path/to/js/dist/source.min.js
+#
+# v2.0
+# https://github.com/cotes2020/jekyll-theme-chirpy
+# © 2020 Cotes Chung
+# MIT Licensed
+
+
+set -eu
+
+PROJ_HOME=$(dirname $(dirname $(realpath "$0")))
+
+YUICOMPRESSOR_SRC=https://github.com/yui/yuicompressor/releases/download/v2.4.8/yuicompressor-2.4.8.jar
+YUICOMPRESSOR=${PROJ_HOME}/tools/package/yuicompressor-2.4.8.jar
+JS_ROOT=${PROJ_HOME}/assets/js/
+JS_SRC=${JS_ROOT}_src    # JS source files
+JS_DEST=${JS_ROOT}dist   # Compressed output directory
+PREFIX_LEN=${#JS_ROOT}   # To beautify the log
+
+
+function init() {
+  if [[ ! -f $YUICOMPRESSOR ]]; then
+    if [[ ! -d "${PROJ_HOME}/tools/package/" ]]; then
+      mkdir -p "${PROJ_HOME}/tools/package/"
+    fi
+    wget "$YUICOMPRESSOR_SRC" -P "${PROJ_HOME}/tools/package/" -q
+  fi
+}
+
+function compress() {
+  # $1 is the source dir
+  # $2 is the destination dir
+  # $3 is the sub dir of source dir, nullable
+  if [[ -z ${3:+unset} ]]
+  then
+    sub_dir=""
+  else
+    sub_dir="$3/"
+  fi
+
+  for item in $(ls $1)
+  do
+    src="$1/$item"
+    if [[ -d "$src" ]]; then
+      compress $src $2 $item   # recursion
+    else
+      if [[ ! -d "$2/${sub_dir}" ]]; then
+        mkdir -p $2/${sub_dir}
+      fi
+      output=$2/${sub_dir}${item%.*}.min.js
+      echo "java -jar $(basename $YUICOMPRESSOR) ${src:$PREFIX_LEN} -o ${output:$PREFIX_LEN}"
+      java -jar $YUICOMPRESSOR $src -o $output
+    fi
+  done
+
+  sub_dir="" # clean up for next recursion.
+}
+
+init
+
+compress $JS_SRC $JS_DEST