Switch to terser as uglifyjs has not been maintained for a while

As a bonus terser supports ES6.

Makefile

@@ -35,7 +35,7 @@ dist: vendor
 	# TODO: cache-invalidation with version string replaced in html file
 	cp -avf public/favicon.ico "dist/${PACKAGE_NAME}-${VERSION}/favicon.ico"
 	$(SASS) -t compressed src/style.scss "dist/${PACKAGE_NAME}-${VERSION}/bundle.css"
-	$(YARN) run -s browserify -t babelify src/index.js | $(YARN) run -s uglifyjs > "dist/${PACKAGE_NAME}-${VERSION}/bundle.js"
+	$(YARN) run -s browserify -t babelify src/index.js | $(YARN) run -s terser --compress --mangle > "dist/${PACKAGE_NAME}-${VERSION}/bundle.js"
 	cd dist && tar --owner=0 --group=0 -czvf ${PACKAGE_NAME}-${VERSION}.tar.gz "${PACKAGE_NAME}-${VERSION}"
 
 

package.json

@@ -17,7 +17,7 @@
     "bulma": "0.9",
     "react": "^16.13.1",
     "react-dom": "^16.13.1",
-    "uglify-js": "^3.9.3"
+    "terser": "^5.0.0"
   },
   "browserslist": "> 0.25%, not dead"
 }

yarn.lock

@@ -1466,6 +1466,11 @@ combine-source-map@^0.8.0, combine-source-map@~0.8.0:
     lodash.memoize "~3.0.3"
     source-map "~0.5.3"
 
+commander@^2.20.0:
+  version "2.20.3"
+  resolved "https://registry.yarnpkg.com/commander/-/commander-2.20.3.tgz#fd485e84c03eb4881c20722ba48035e8531aeb33"
+  integrity sha512-GpVkmM8vF2vQUkj2LvZmD35JxeJOLCwJ9cUkugyk2nuhbv3+mJvpLYYt+0+USMxE+oj+ey/lJEnhZw75x/OMcQ==
+
 component-emitter@^1.2.1:
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/component-emitter/-/component-emitter-1.3.0.tgz#16e4070fba8ae29b679f2215853ee181ab2eabc0"
@@ -3309,6 +3314,14 @@ source-map-resolve@^0.5.0:
     source-map-url "^0.4.0"
     urix "^0.1.0"
 
+source-map-support@~0.5.12:
+  version "0.5.19"
+  resolved "https://registry.yarnpkg.com/source-map-support/-/source-map-support-0.5.19.tgz#a98b62f86dcaf4f67399648c085291ab9e8fed61"
+  integrity sha512-Wonm7zOCIJzBGQdB+thsPar0kYuCIzYvxZwlBa87yi/Mdjv7Tip2cyVbLj5o0cFPN4EVkuTwb3GDDyUx2DGnGw==
+  dependencies:
+    buffer-from "^1.0.0"
+    source-map "^0.6.0"
+
 source-map-url@^0.4.0:
   version "0.4.0"
   resolved "https://registry.yarnpkg.com/source-map-url/-/source-map-url-0.4.0.tgz#3e935d7ddd73631b97659956d55128e87b5084a3"
@@ -3319,6 +3332,11 @@ source-map@^0.5.0, source-map@^0.5.6, source-map@~0.5.3:
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.7.tgz#8a039d2d1021d22d1ea14c80d8ea468ba2ef3fcc"
   integrity sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=
 
+source-map@^0.6.0, source-map@~0.6.1:
+  version "0.6.1"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
+  integrity sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==
+
 split-string@^3.0.1, split-string@^3.0.2:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/split-string/-/split-string-3.1.0.tgz#7cb09dda3a86585705c64b39a6466038682e8fe2"
@@ -3474,6 +3492,15 @@ term-color@^1.0.1:
     ansi-styles "2.0.1"
     supports-color "1.3.1"
 
+terser@^5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/terser/-/terser-5.0.0.tgz#269640e4e92f15d628de1e5f01c4c61e1ba3d765"
+  integrity sha512-olH2DwGINoSuEpSGd+BsPuAQaA3OrHnHnFL/rDB2TVNc3srUbz/rq/j2BlF4zDXI+JqAvGr86bIm1R2cJgZ3FA==
+  dependencies:
+    commander "^2.20.0"
+    source-map "~0.6.1"
+    source-map-support "~0.5.12"
+
 through2@^2.0.0:
   version "2.0.5"
   resolved "https://registry.yarnpkg.com/through2/-/through2-2.0.5.tgz#01c1e39eb31d07cb7d03a96a70823260b23132cd"
@@ -3547,11 +3574,6 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
-uglify-js@^3.9.3:
-  version "3.10.0"
-  resolved "https://registry.yarnpkg.com/uglify-js/-/uglify-js-3.10.0.tgz#397a7e6e31ce820bfd1cb55b804ee140c587a9e7"
-  integrity sha512-Esj5HG5WAyrLIdYU74Z3JdG2PxdIusvj6IWHMtlyESxc7kcDz7zYlYjpnSokn1UbpV0d/QX9fan7gkCNd/9BQA==
-
 umd@^3.0.0:
   version "3.0.3"
   resolved "https://registry.yarnpkg.com/umd/-/umd-3.0.3.tgz#aa9fe653c42b9097678489c01000acb69f0b26cf"