Revert "Revert "stale: Terser instead of uglify (#4075)""

This reverts commit 423be7f081.

src/node/utils/Minify.js

@@ -23,8 +23,6 @@ var ERR = require("async-stacktrace");
 var settings = require('./Settings');
 var async = require('async');
 var fs = require('fs');
-var StringDecoder = require('string_decoder').StringDecoder;
-var CleanCSS = require('clean-css');
 var path = require('path');
 var plugins = require("ep_etherpad-lite/static/js/pluginfw/plugins");
 var RequireKernel = require('etherpad-require-kernel');

src/node/utils/MinifyWorker.js

@@ -3,13 +3,13 @@
  */
 
 var CleanCSS = require('clean-css');
-var uglifyJS = require("uglify-js");
+var terser = require("terser");
 var path = require('path');
 var Threads = require('threads')
 
 function compressJS(content)
 {
-  return uglifyJS.minify(content);
+  return terser.minify(content);
 }
 
 function compressCSS(filename, ROOT_DIR)

src/package.json

@@ -62,11 +62,11 @@
     "semver": "5.6.0",
     "slide": "1.1.6",
     "socket.io": "2.1.1",
+    "terser": "^4.7.0",
     "threads": "^1.4.0",
     "tiny-worker": "^2.3.0",
     "tinycon": "0.0.1",
     "ueberdb2": "0.4.9",
-    "uglify-js": "3.8.1",
     "underscore": "1.8.3",
     "unorm": "1.4.1"
   },