Issue 3673 - Merge closely matching rules

abp2blocklist.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 "use strict";
 
 let readline = require("readline");
 let Filter = require("filterClasses").Filter;
 let ContentBlockerList = require("./lib/abp2blocklist.js").ContentBlockerList;
 
 var rl = readline.createInterface({input: process.stdin, terminal: false});
-var blockerList = new ContentBlockerList();
+var blockerList = new ContentBlockerList({merge: "all"});
 
 rl.on("line", line =>
 {
   if (/^\s*[^\[\s]/.test(line))
     blockerList.addFilter(Filter.fromText(Filter.normalize(line)));
 });
 
 rl.on("close", () =>
 {
-  console.log(JSON.stringify(blockerList.generateRules({merge: true}), null,
-                             "\t"));
+  blockerList.generateRules().then(rules =>
+  {
+    // If the rule set is too huge, JSON.stringify throws
+    // "RangeError: Invalid string length" on Node.js. As a workaround, print
+    // each rule individually.
+    console.log("[");
+    if (rules.length > 0)
+    {
+      let stringifyRule = rule => JSON.stringify(rule, null, "\t");
+      for (let i = 0; i < rules.length - 1; i++)
+        console.log(stringifyRule(rules[i]) + ",");
+      console.log(stringifyRule(rules[rules.length - 1]));
+    }
+    console.log("]");
+  });
 });