diff --git a/extensions/javascript/syntaxes/JavaScript.tmLanguage.json b/extensions/javascript/syntaxes/JavaScript.tmLanguage.json
index 3e9a33e4824..e243d04c4b5 100644
--- a/extensions/javascript/syntaxes/JavaScript.tmLanguage.json
+++ b/extensions/javascript/syntaxes/JavaScript.tmLanguage.json
@@ -1064,6 +1064,9 @@
 				{
 					"include": "#indexer-declaration"
 				},
+				{
+					"include": "#indexer-mapped-type-declaration"
+				},
 				{
 					"include": "#field-declaration"
 				},
@@ -1269,6 +1272,38 @@
 				}
 			]
 		},
+		"indexer-mapped-type-declaration": {
+			"name": "meta.indexer.mappedtype.declaration.js",
+			"begin": "(?:(?<!\\.|\\$)\\b(readonly)\\s*)?(\\[)\\s*([_$[:alpha:]][_$[:alnum:]]*)\\s+(in)\\s+",
+			"beginCaptures": {
+				"1": {
+					"name": "storage.modifier.js"
+				},
+				"2": {
+					"name": "meta.brace.square.js"
+				},
+				"3": {
+					"name": "entity.name.type.js"
+				},
+				"4": {
+					"name": "keyword.operator.expression.in.js"
+				}
+			},
+			"end": "(\\])\\s*(\\?\\s*)?|$",
+			"endCaptures": {
+				"1": {
+					"name": "meta.brace.square.js"
+				},
+				"2": {
+					"name": "keyword.operator.optional.js"
+				}
+			},
+			"patterns": [
+				{
+					"include": "#type"
+				}
+			]
+		},
 		"function-declaration": {
 			"name": "meta.function.js",
 			"begin": "(?<!\\.|\\$)\\b(?:(export)\\s+)?(?:(async)\\s+)?(function\\b)(?:\\s*(\\*))?(?:(?:\\s+|(?<=\\*))([_$[:alpha:]][_$[:alnum:]]*))?\\s*",
@@ -2780,7 +2815,7 @@
 				},
 				{
 					"name": "string.regex.js",
-					"begin": "/(?![/*])(?=(?:[^/\\\\\\[]|\\\\.|\\[([^\\]\\\\]|\\\\.)+\\])+/(?![/*])[gimy]*(?!\\s*[a-zA-Z0-9_$]))",
+					"begin": "(?<![_$[:alnum:]])/(?![/*])(?=(?:[^/\\\\\\[]|\\\\.|\\[([^\\]\\\\]|\\\\.)+\\])+/(?![/*])[gimy]*(?!\\s*[a-zA-Z0-9_$]))",
 					"beginCaptures": {
 						"0": {
 							"name": "punctuation.definition.string.begin.js"
@@ -3571,5 +3606,5 @@
 			]
 		}
 	},
-	"version": "https://github.com/Microsoft/TypeScript-TmLanguage/commit/4d0bdebb93aadc25ecbb903ebc897e9cd5fab69c"
+	"version": "https://github.com/Microsoft/TypeScript-TmLanguage/commit/b5ce6b5632711b9230a33213874b818d994acab9"
 }
\ No newline at end of file
diff --git a/extensions/typescript/syntaxes/TypeScript.tmLanguage.json b/extensions/typescript/syntaxes/TypeScript.tmLanguage.json
index 1ae0e596524..bdedff59d5d 100644
--- a/extensions/typescript/syntaxes/TypeScript.tmLanguage.json
+++ b/extensions/typescript/syntaxes/TypeScript.tmLanguage.json
@@ -1060,6 +1060,9 @@
 				{
 					"include": "#indexer-declaration"
 				},
+				{
+					"include": "#indexer-mapped-type-declaration"
+				},
 				{
 					"include": "#field-declaration"
 				},
@@ -1265,6 +1268,38 @@
 				}
 			]
 		},
+		"indexer-mapped-type-declaration": {
+			"name": "meta.indexer.mappedtype.declaration.ts",
+			"begin": "(?:(?<!\\.|\\$)\\b(readonly)\\s*)?(\\[)\\s*([_$[:alpha:]][_$[:alnum:]]*)\\s+(in)\\s+",
+			"beginCaptures": {
+				"1": {
+					"name": "storage.modifier.ts"
+				},
+				"2": {
+					"name": "meta.brace.square.ts"
+				},
+				"3": {
+					"name": "entity.name.type.ts"
+				},
+				"4": {
+					"name": "keyword.operator.expression.in.ts"
+				}
+			},
+			"end": "(\\])\\s*(\\?\\s*)?|$",
+			"endCaptures": {
+				"1": {
+					"name": "meta.brace.square.ts"
+				},
+				"2": {
+					"name": "keyword.operator.optional.ts"
+				}
+			},
+			"patterns": [
+				{
+					"include": "#type"
+				}
+			]
+		},
 		"function-declaration": {
 			"name": "meta.function.ts",
 			"begin": "(?<!\\.|\\$)\\b(?:(export)\\s+)?(?:(async)\\s+)?(function\\b)(?:\\s*(\\*))?(?:(?:\\s+|(?<=\\*))([_$[:alpha:]][_$[:alnum:]]*))?\\s*",
@@ -2789,7 +2824,7 @@
 				},
 				{
 					"name": "string.regex.ts",
-					"begin": "/(?![/*])(?=(?:[^/\\\\\\[]|\\\\.|\\[([^\\]\\\\]|\\\\.)+\\])+/(?![/*])[gimy]*(?!\\s*[a-zA-Z0-9_$]))",
+					"begin": "(?<![_$[:alnum:]])/(?![/*])(?=(?:[^/\\\\\\[]|\\\\.|\\[([^\\]\\\\]|\\\\.)+\\])+/(?![/*])[gimy]*(?!\\s*[a-zA-Z0-9_$]))",
 					"beginCaptures": {
 						"0": {
 							"name": "punctuation.definition.string.begin.ts"
@@ -3299,5 +3334,5 @@
 			]
 		}
 	},
-	"version": "https://github.com/Microsoft/TypeScript-TmLanguage/commit/4d0bdebb93aadc25ecbb903ebc897e9cd5fab69c"
+	"version": "https://github.com/Microsoft/TypeScript-TmLanguage/commit/b5ce6b5632711b9230a33213874b818d994acab9"
 }
\ No newline at end of file
diff --git a/extensions/typescript/syntaxes/TypeScriptReact.tmLanguage.json b/extensions/typescript/syntaxes/TypeScriptReact.tmLanguage.json
index abffb2a6da5..3141936274a 100644
--- a/extensions/typescript/syntaxes/TypeScriptReact.tmLanguage.json
+++ b/extensions/typescript/syntaxes/TypeScriptReact.tmLanguage.json
@@ -1063,6 +1063,9 @@
 				{
 					"include": "#indexer-declaration"
 				},
+				{
+					"include": "#indexer-mapped-type-declaration"
+				},
 				{
 					"include": "#field-declaration"
 				},
@@ -1268,6 +1271,38 @@
 				}
 			]
 		},
+		"indexer-mapped-type-declaration": {
+			"name": "meta.indexer.mappedtype.declaration.tsx",
+			"begin": "(?:(?<!\\.|\\$)\\b(readonly)\\s*)?(\\[)\\s*([_$[:alpha:]][_$[:alnum:]]*)\\s+(in)\\s+",
+			"beginCaptures": {
+				"1": {
+					"name": "storage.modifier.tsx"
+				},
+				"2": {
+					"name": "meta.brace.square.tsx"
+				},
+				"3": {
+					"name": "entity.name.type.tsx"
+				},
+				"4": {
+					"name": "keyword.operator.expression.in.tsx"
+				}
+			},
+			"end": "(\\])\\s*(\\?\\s*)?|$",
+			"endCaptures": {
+				"1": {
+					"name": "meta.brace.square.tsx"
+				},
+				"2": {
+					"name": "keyword.operator.optional.tsx"
+				}
+			},
+			"patterns": [
+				{
+					"include": "#type"
+				}
+			]
+		},
 		"function-declaration": {
 			"name": "meta.function.tsx",
 			"begin": "(?<!\\.|\\$)\\b(?:(export)\\s+)?(?:(async)\\s+)?(function\\b)(?:\\s*(\\*))?(?:(?:\\s+|(?<=\\*))([_$[:alpha:]][_$[:alnum:]]*))?\\s*",
@@ -2779,7 +2814,7 @@
 				},
 				{
 					"name": "string.regex.tsx",
-					"begin": "/(?![/*])(?=(?:[^/\\\\\\[]|\\\\.|\\[([^\\]\\\\]|\\\\.)+\\])+/(?![/*])[gimy]*(?!\\s*[a-zA-Z0-9_$]))",
+					"begin": "(?<![_$[:alnum:]])/(?![/*])(?=(?:[^/\\\\\\[]|\\\\.|\\[([^\\]\\\\]|\\\\.)+\\])+/(?![/*])[gimy]*(?!\\s*[a-zA-Z0-9_$]))",
 					"beginCaptures": {
 						"0": {
 							"name": "punctuation.definition.string.begin.tsx"
@@ -3570,5 +3605,5 @@
 			]
 		}
 	},
-	"version": "https://github.com/Microsoft/TypeScript-TmLanguage/commit/4d0bdebb93aadc25ecbb903ebc897e9cd5fab69c"
+	"version": "https://github.com/Microsoft/TypeScript-TmLanguage/commit/b5ce6b5632711b9230a33213874b818d994acab9"
 }
\ No newline at end of file