From 2f5590ea7846f0207430daa857a7dbb9cd74930b Mon Sep 17 00:00:00 2001
From: Antoine du Hamel <duhamelantoine1995@gmail.com>
Date: Mon, 15 Feb 2021 12:25:15 -0500
Subject: [PATCH] ehn(parser): add unregisterLanguage method (#3009)

---
 .eslintrc.js                   |  3 +++
 CHANGES.md                     |  5 +++++
 docs/api.rst                   |  8 +++++++
 src/highlight.js               | 15 +++++++++++++
 test/api/index.js              |  1 +
 test/api/unregisterLanguage.js | 39 ++++++++++++++++++++++++++++++++++
 types/index.d.ts               |  1 +
 7 files changed, 72 insertions(+)
 create mode 100644 test/api/unregisterLanguage.js

diff --git a/.eslintrc.js b/.eslintrc.js
index a5470241fd..6027b3ec49 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -90,6 +90,9 @@ module.exports = {
     },
     {
       files: ["test/**/*.js"],
+      globals: {
+        should: "readonly"
+      },
       env: {
         mocha: true
       },
diff --git a/CHANGES.md b/CHANGES.md
index 36ff62e2f3..c2946f1ecf 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -14,12 +14,17 @@ Language grammar improvements:
 - enh(php) Add `mixed` to list of keywords (#2997) [Ayesh][]
 - enh(php) Add support binary, octal, hex and scientific numerals with underscore separator support (#2997) [Ayesh][]
 
+API:
+
+- enh(api) add `unregisterLanguage` method (#3009) [Antoine du Hamel][]
+
 [Stef Levesque]: https://github.com/stef-levesque
 [Josh Goebel]: https://github.com/joshgoebel
 [John Cheung]: https://github.com/Real-John-Cheung
 [xDGameStudios]: https://github.com/xDGameStudios
 [Ayesh]: https://github.com/Ayesh
 [Vyron Vasileiadis]: https://github.com/fedonman
+[Antoine du Hamel]: https://github.com/aduh95
 
 ## Version 10.6.0
 
diff --git a/docs/api.rst b/docs/api.rst
index 237c6eb1b9..3c2936b0d4 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -125,6 +125,14 @@ Adds new language to the library under the specified name. Used mostly internall
   to use common regular expressions defined within it.
 
 
+``unregisterLanguage(languageName)``
+------------------------------------
+
+Removes a language and its aliases from the library. Used mostly internally.
+
+* ``languageName``: a string with the name of the language being removed.
+
+
 ``registerAliases(alias|aliases, {languageName})``
 --------------------------------------------------
 
diff --git a/src/highlight.js b/src/highlight.js
index 9caad5795e..ef03ab36c6 100644
--- a/src/highlight.js
+++ b/src/highlight.js
@@ -814,6 +814,20 @@ const HLJS = function(hljs) {
     }
   }
 
+  /**
+   * Remove a language grammar module
+   *
+   * @param {string} languageName
+   */
+  function unregisterLanguage(languageName) {
+    delete languages[languageName];
+    for (const alias of Object.keys(aliases)) {
+      if (aliases[alias] === languageName) {
+        delete aliases[alias];
+      }
+    }
+  }
+
   /**
    * @returns {string[]} List of language internal names
    */
@@ -916,6 +930,7 @@ const HLJS = function(hljs) {
     initHighlighting,
     initHighlightingOnLoad,
     registerLanguage,
+    unregisterLanguage,
     listLanguages,
     getLanguage,
     registerAliases,
diff --git a/test/api/index.js b/test/api/index.js
index 223fbc0e30..b15ed29936 100644
--- a/test/api/index.js
+++ b/test/api/index.js
@@ -12,6 +12,7 @@ describe('hljs', function() {
   require('./keywords');
   require('./number');
   require('./registerAlias');
+  require('./unregisterLanguage');
   require('./starters');
   require('./underscoreIdent');
 });
diff --git a/test/api/unregisterLanguage.js b/test/api/unregisterLanguage.js
new file mode 100644
index 0000000000..ce0ff00b99
--- /dev/null
+++ b/test/api/unregisterLanguage.js
@@ -0,0 +1,39 @@
+"use strict";
+
+const hljs = require("../../build");
+
+const jQuery = function() {
+  return {
+    name: "jQuery",
+    contains: [{ beginKeywords: "class" }]
+  };
+};
+
+describe(".unregisterLanguage()", () => {
+  beforeEach(() => {
+    hljs.registerLanguage("test", jQuery);
+  });
+
+  it("should remove an existing language", () => {
+    hljs.unregisterLanguage("test");
+    const result = hljs.getLanguage("test");
+
+    should(result).be.undefined();
+  });
+
+  it("should remove an existing language and its aliases", () => {
+    hljs.registerAliases(["jquery", "jqueryui"], {
+      languageName: "test"
+    });
+
+    {
+      const result = hljs.getLanguage("jquery");
+      should(result.name).equal("jQuery");
+    }
+    hljs.unregisterLanguage("test");
+    {
+      const result = hljs.getLanguage("jquery");
+      should(result).be.undefined();
+    }
+  });
+});
diff --git a/types/index.d.ts b/types/index.d.ts
index 825ad72301..d5caf9054f 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -24,6 +24,7 @@ interface PublicApi {
     initHighlightingOnLoad: () => void
     highlightAll: () => void
     registerLanguage: (languageName: string, language: LanguageFn) => void
+    unregisterLanguage: (languageName: string) => void
     listLanguages: () => string[]
     registerAliases: (aliasList: string | string[], { languageName } : {languageName: string}) => void
     getLanguage: (languageName: string) => Language | undefined