diff --git a/CHANGES.md b/CHANGES.md
index 5363f68b3d..e6e1f1f4a9 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -22,6 +22,9 @@ New Languages:
 
 Language Improvements:
 
+- fix(r) fixed keywords not properly spaced (#2852) [Josh Goebel][]
+- fix(javascript) fix potential catastrophic backtracking (#2852) [Josh Goebel][]
+- fix(livescript) fix potential catastrophic backtracking (#2852) [Josh Goebel][]
 - bug(xml) XML grammar was far too imprecise/fuzzy [Josh Goebel][]
 - enh(xml) Improve precision to prevent false auto-detect positives [Josh Goebel][]
 - fix(js/ts) Prevent for/while/if/switch from falsly matching as functions (#2803) [Josh Goebel][]
diff --git a/src/languages/1c.js b/src/languages/1c.js
index d40f539ec5..595aaeca58 100644
--- a/src/languages/1c.js
+++ b/src/languages/1c.js
@@ -515,5 +515,5 @@ export default function(hljs) {
       STRINGS,
       DATE
     ]
-  }
+  };
 }
diff --git a/src/languages/hy.js b/src/languages/hy.js
index b86d6f787f..fe913e10df 100644
--- a/src/languages/hy.js
+++ b/src/languages/hy.js
@@ -101,5 +101,5 @@ export default function(hljs) {
     aliases: ['hylang'],
     illegal: /\S/,
     contains: [hljs.SHEBANG(), LIST, STRING, HINT, HINT_COL, COMMENT, KEY, COLLECTION, NUMBER, LITERAL]
-  }
+  };
 }
diff --git a/src/languages/java.js b/src/languages/java.js
index 9c949f726c..1e9ab182dc 100644
--- a/src/languages/java.js
+++ b/src/languages/java.js
@@ -5,8 +5,6 @@ Category: common, enterprise
 Website: https://www.java.com/
 */
 
-import * as regex from '../lib/regex.js';
-
 export default function(hljs) {
   var JAVA_IDENT_RE = '[\u00C0-\u02B8a-zA-Z_$][\u00C0-\u02B8a-zA-Z_$0-9]*';
   var GENERIC_IDENT_RE = JAVA_IDENT_RE + '(<' + JAVA_IDENT_RE + '(\\s*,\\s*' + JAVA_IDENT_RE + ')*>)?';
diff --git a/src/languages/javascript.js b/src/languages/javascript.js
index bb077d6138..2bccc2190c 100644
--- a/src/languages/javascript.js
+++ b/src/languages/javascript.js
@@ -18,7 +18,7 @@ export default function(hljs) {
    * @param {{after:number}} param1
    */
   const hasClosingTag = (match, { after }) => {
-    const tag = match[0].replace("<", "</");
+    const tag = "</" + match[0].slice(1);
     const pos = match.input.indexOf(tag, after);
     return pos !== -1;
   };
@@ -256,9 +256,7 @@ export default function(hljs) {
           regex.lookahead(regex.concat(
             // we also need to allow for multiple possible comments inbetween
             // the first key:value pairing
-            /(\/\/.*$)*/,
-            /(\/\*(.|\n)*\*\/)*/,
-            /\s*/,
+            /(((\/\/.*$)|(\/\*(\*[^/]|[^*])*\*\/))\s*)*/,
             IDENT_RE + '\\s*:'))),
         relevance: 0,
         contains: [
diff --git a/src/languages/kotlin.js b/src/languages/kotlin.js
index e2610a9412..6de5532d04 100644
--- a/src/languages/kotlin.js
+++ b/src/languages/kotlin.js
@@ -66,7 +66,7 @@ export default function(hljs) {
       }
     ]
   };
-  SUBST.contains.push(STRING)
+  SUBST.contains.push(STRING);
 
   var ANNOTATION_USE_SITE = {
     className: 'meta', begin: '@(?:file|property|field|get|set|receiver|param|setparam|delegate)\\s*:(?:\\s*' + hljs.UNDERSCORE_IDENT_RE + ')?'
diff --git a/src/languages/livescript.js b/src/languages/livescript.js
index c8e9f81301..6d5f4abf15 100644
--- a/src/languages/livescript.js
+++ b/src/languages/livescript.js
@@ -115,7 +115,7 @@ export default function(hljs) {
         {
           // regex can't start with space to parse x / 2 / 3 as two divisions
           // regex can't start with *, and it supports an "illegal" in the main mode
-          begin: /\/(?![ *])(\\\/|.)*?\/[gim]*(?=\W)/
+          begin: /\/(?![ *])(\\.|[^\\\n])*?\/[gim]*(?=\W)/
         }
       ]
     },
diff --git a/src/languages/mercury.js b/src/languages/mercury.js
index eeab89f5e6..ece8023bd4 100644
--- a/src/languages/mercury.js
+++ b/src/languages/mercury.js
@@ -49,7 +49,7 @@ export default function(hljs) {
     begin: '\\\\[abfnrtv]\\|\\\\x[0-9a-fA-F]*\\\\\\|%[-+# *.0-9]*[dioxXucsfeEgGp]',
     relevance: 0
   };
-  STRING.contains = STRING.contains.slice() // we need our own copy of contains
+  STRING.contains = STRING.contains.slice(); // we need our own copy of contains
   STRING.contains.push(STRING_FMT);
 
   var IMPLICATION = {
diff --git a/src/languages/parser3.js b/src/languages/parser3.js
index 18ee3634ae..e300fc4109 100644
--- a/src/languages/parser3.js
+++ b/src/languages/parser3.js
@@ -20,7 +20,7 @@ export default function(hljs) {
     contains: [
       hljs.COMMENT('^#', '$'),
       hljs.COMMENT(
-        /\\^rem\{/,
+        /\^rem\{/,
         /\}/,
         {
           relevance: 10,
diff --git a/src/languages/powershell.js b/src/languages/powershell.js
index 5e80f4714d..98523c0d82 100644
--- a/src/languages/powershell.js
+++ b/src/languages/powershell.js
@@ -242,7 +242,7 @@ export default function(hljs) {
     )
   };
 
-  PS_METHODS.contains.unshift(PS_TYPE)
+  PS_METHODS.contains.unshift(PS_TYPE);
 
   return {
     name: 'PowerShell',
diff --git a/src/languages/r.js b/src/languages/r.js
index b095333004..82a9874882 100644
--- a/src/languages/r.js
+++ b/src/languages/r.js
@@ -32,22 +32,22 @@ export default function(hljs) {
         // Primitive functions
         // These are all the functions in `base` that are implemented as a
         // `.Primitive`, minus those functions that are also keywords.
-        'abs acos acosh all any anyNA Arg as.call as.character' +
-        'as.complex as.double as.environment as.integer as.logical' +
-        'as.null.default as.numeric as.raw asin asinh atan atanh attr' +
-        'attributes baseenv browser c call ceiling class Conj cos cosh' +
-        'cospi cummax cummin cumprod cumsum digamma dim dimnames' +
-        'emptyenv exp expression floor forceAndCall gamma gc.time' +
-        'globalenv Im interactive invisible is.array is.atomic is.call' +
-        'is.character is.complex is.double is.environment is.expression' +
-        'is.finite is.function is.infinite is.integer is.language' +
-        'is.list is.logical is.matrix is.na is.name is.nan is.null' +
-        'is.numeric is.object is.pairlist is.raw is.recursive is.single' +
-        'is.symbol lazyLoadDBfetch length lgamma list log max min' +
-        'missing Mod names nargs nzchar oldClass on.exit pos.to.env' +
-        'proc.time prod quote range Re rep retracemem return round' +
-        'seq_along seq_len seq.int sign signif sin sinh sinpi sqrt' +
-        'standardGeneric substitute sum switch tan tanh tanpi tracemem' +
+        'abs acos acosh all any anyNA Arg as.call as.character ' +
+        'as.complex as.double as.environment as.integer as.logical ' +
+        'as.null.default as.numeric as.raw asin asinh atan atanh attr ' +
+        'attributes baseenv browser c call ceiling class Conj cos cosh ' +
+        'cospi cummax cummin cumprod cumsum digamma dim dimnames ' +
+        'emptyenv exp expression floor forceAndCall gamma gc.time ' +
+        'globalenv Im interactive invisible is.array is.atomic is.call ' +
+        'is.character is.complex is.double is.environment is.expression ' +
+        'is.finite is.function is.infinite is.integer is.language ' +
+        'is.list is.logical is.matrix is.na is.name is.nan is.null ' +
+        'is.numeric is.object is.pairlist is.raw is.recursive is.single ' +
+        'is.symbol lazyLoadDBfetch length lgamma list log max min ' +
+        'missing Mod names nargs nzchar oldClass on.exit pos.to.env ' +
+        'proc.time prod quote range Re rep retracemem return round ' +
+        'seq_along seq_len seq.int sign signif sin sinh sinpi sqrt ' +
+        'standardGeneric substitute sum switch tan tanh tanpi tracemem ' +
         'trigamma trunc unclass untracemem UseMethod xtfrm',
     },
 
diff --git a/src/languages/swift.js b/src/languages/swift.js
index 7034f24f45..ad38d8777f 100644
--- a/src/languages/swift.js
+++ b/src/languages/swift.js
@@ -50,7 +50,7 @@ export default function(hljs) {
   var OPTIONAL_USING_TYPE = {
     className: 'type',
     begin: '\\b[A-Z][\\w\u00C0-\u02B8\']*[!?]'
-  }
+  };
   var BLOCK_COMMENT = hljs.COMMENT(
     '/\\*',
     '\\*/',
diff --git a/tools/developer.html b/tools/developer.html
index 3ef72618a5..6a53a8abfd 100644
--- a/tools/developer.html
+++ b/tools/developer.html
@@ -57,7 +57,7 @@
     }
   </style>
 </head>
-<body id>
+<body>
   <div class="editor" id="app">
     <h3>Code</h3>
     <div>
@@ -295,7 +295,7 @@ <h3>Markup</h3>
           this.refreshKlass();
         }
       }
-    })
+    });
   </script>
 </body>
 </html>