chore: rename registerAlias to registerAliases

Plural form is clearly better as it's not surprising to the reader
to see it being passed an array - where as the singular form might
have been.  Meanwhile it's also easy to assume that it also supports
arrays of any size - including an array with a singular alias.

The fact that it can magically accept a string as the first argument
might not be obvious, but we document it and even if one didn't know
this they could still use the array form of the API without any issue
by passing a one item array.

CHANGES.md

@@ -4,7 +4,7 @@ Parser Engine:
 
 - (parser) Adds `keywords.$pattern` key to grammar definitions (#2519) [Josh Goebel][]
 - (parser) Adds SHEBANG utility mode [Josh Goebel][]
-- (parser) Adds `registerAlias` method (#2540) [Taufik Nurrohman][]
+- (parser) Adds `registerAliases` method (#2540) [Taufik Nurrohman][]
 - (enh) Added `on:begin` callback for modes (#2261) [Josh Goebel][]
 - (enh) Added `on:end` callback for modes (#2261) [Josh Goebel][]
 - (enh) Added ability to programatically ignore begin and end matches (#2261) [Josh Goebel][]

docs/api.rst

@@ -112,8 +112,8 @@ Adds new language to the library under the specified name. Used mostly internall
   to use common regular expressions defined within it.
 
 
-``registerAlias(alias|aliases, {languageName})``
-------------------------------------------------
+``registerAliases(alias|aliases, {languageName})``
+--------------------------------------------------
 
 Adds new language alias or aliases to the library for the specified language name defined under ``languageName`` key.
 

src/highlight.js

@@ -658,7 +658,7 @@ const HLJS = function(hljs) {
     lang.rawDefinition = language.bind(null, hljs);
 
     if (lang.aliases) {
-      lang.aliases.forEach(function(alias) { aliases[alias] = name; });
+      registerAliases(lang.aliases, { languageName: name });
     }
   }
 
@@ -685,12 +685,11 @@ const HLJS = function(hljs) {
     return languages[name] || languages[aliases[name]];
   }
 
-  function registerAlias(alias, {languageName}) {
-    let list = alias;
-    if (typeof list === 'string') {
-      list = [alias]
+  function registerAliases(aliasList, {languageName}) {
+    if (typeof aliasList === 'string') {
+      aliasList = [aliasList]
     }
-    list.forEach(alias => aliases[alias] = languageName);
+    aliasList.forEach(alias => aliases[alias] = languageName);
   }
 
   function autoDetection(name) {
@@ -724,7 +723,7 @@ const HLJS = function(hljs) {
     registerLanguage,
     listLanguages,
     getLanguage,
-    registerAlias,
+    registerAliases,
     requireLanguage,
     autoDetection,
     inherit,

test/api/index.js

@@ -12,4 +12,5 @@ describe('hljs', function() {
   require('./highlight');
   require('./fixmarkup');
   require('./keywords');
+  require('./registerAlias');
 });

test/api/registerAlias.js

@@ -3,9 +3,9 @@
 const hljs   = require('../../build');
 const should = require('should');
 
-describe('.registerAlias()', () => {
+describe('.registerAliases()', () => {
   it('should get an existing language by alias', () => {
-    hljs.registerAlias('jquery', {
+    hljs.registerAliases('jquery', {
       languageName: 'javascript'
     });
     const result = hljs.getLanguage('jquery');
@@ -14,7 +14,7 @@ describe('.registerAlias()', () => {
   });
 
   it('should get an existing language by aliases', () => {
-    hljs.registerAlias(['jquery', 'jqueryui'], {
+    hljs.registerAliases(['jquery', 'jqueryui'], {
       languageName: 'javascript'
     });
     const result = hljs.getLanguage('jquery');