From 97b3069af3443cd721de8c5409fb9a8242ac0fc2 Mon Sep 17 00:00:00 2001
From: HoJeong Go <seia@outlook.kr>
Date: Wed, 10 Jan 2024 16:29:09 +0900
Subject: [PATCH] feat: modifier replacer for NetworkFilter.toString (#3699)

* feat: modifier replacer for NetworkFilter.toString

To make minimal performance impact on current codes using adblocker library, I chose to use Array.prototype.map function instead of putting `if` statements or using empty proxying function: `(str: text) => str` as default value.

refs https://github.com/ghostery/adblocker/issues/3693

* chore: fix types

use `as const` keyword

* chore(test): fix test output

refs https://github.com/ghostery/adblocker/pull/3681

* fix(test): test expectation to match latest commit

refs #3681
---
 packages/adblocker/src/filters/network.ts |  8 ++++++--
 packages/adblocker/test/parsing.test.ts   | 23 +++++++++++++++++++----
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/packages/adblocker/src/filters/network.ts b/packages/adblocker/src/filters/network.ts
index 8c8640e6a8..8ade11380e 100644
--- a/packages/adblocker/src/filters/network.ts
+++ b/packages/adblocker/src/filters/network.ts
@@ -1087,7 +1087,7 @@ export default class NetworkFilter implements IFilter {
    * there are things which cannot be recovered though, like domains options
    * of which only hashes are stored.
    */
-  public toString() {
+  public toString(modifierReplacer?: (modifier: string) => string) {
     if (this.rawLine !== undefined) {
       return this.rawLine;
     }
@@ -1201,7 +1201,11 @@ export default class NetworkFilter implements IFilter {
     }
 
     if (options.length > 0) {
-      filter += `$${options.join(',')}`;
+      if (typeof modifierReplacer === 'function') {
+        filter += `$${options.map(modifierReplacer).join(',')}`;
+      } else {
+        filter += `$${options.join(',')}`;
+      }
     }
 
     return filter;
diff --git a/packages/adblocker/test/parsing.test.ts b/packages/adblocker/test/parsing.test.ts
index 166401b40d..79fc46726f 100644
--- a/packages/adblocker/test/parsing.test.ts
+++ b/packages/adblocker/test/parsing.test.ts
@@ -117,11 +117,16 @@ const DEFAULT_NETWORK_FILTER = {
 
 describe('Network filters', () => {
   describe('toString', () => {
-    const checkToString = (line: string, expected: string, debug: boolean = false) => {
+    const checkToString = (
+      line: string,
+      expected: string,
+      debug: boolean = false,
+      modifierReplacer = (modifier: string) => modifier,
+    ) => {
       const parsed = NetworkFilter.parse(line, debug);
       expect(parsed).not.to.be.null;
       if (parsed !== null) {
-        expect(parsed.toString()).to.equal(expected);
+        expect(parsed.toString(modifierReplacer)).to.equal(expected);
       }
     };
 
@@ -178,6 +183,16 @@ describe('Network filters', () => {
         true,
       );
     });
+
+    it('pprint longer form of modifiers', () => {
+      checkToString('||foo.com^$3p', '||foo.com^$third-party', false, (modifier) => {
+        if (modifier === '3p') {
+          return 'third-party';
+        }
+
+        return modifier;
+      });
+    });
   });
 
   it('parses pattern', () => {
@@ -1365,9 +1380,9 @@ describe('Network filters', () => {
         [new Uint32Array([NORMALIZED_TYPE_TOKEN.document])],
       ],
       ['@@/wp-content/themes/$script', [hashStrings(['content'])]],
-    ]) {
+    ] as const) {
       it(`get tokens for ${filter}`, () => {
-        const parsed = NetworkFilter.parse(filter as string, true);
+        const parsed = NetworkFilter.parse(filter, true);
         expect(parsed).not.to.be.null;
         if (parsed !== null) {
           expect(parsed.getTokens()).to.eql(regexTokens);