diff --git a/components/prism-javascript.js b/components/prism-javascript.js
index ac175e1932..f215e5eb16 100644
--- a/components/prism-javascript.js
+++ b/components/prism-javascript.js
@@ -19,16 +19,22 @@ Prism.languages.insertBefore('javascript', 'keyword', {
 	},
 	'parameter': [
 		{
-			pattern: /(function)(?:\s+[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)?\s*(\([^()]*\))/,
+			pattern: /(function(?:\s+[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)?\s*\(\s*)\S[^()]*(?=\s*\))/,
 			lookbehind: true,
 			inside: Prism.languages.javascript
 		},
 		{
-			pattern: /(\([^()]*\)|[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)(?=\s*=>)/,
+			pattern: /[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*(?=\s*=>)/,
 			inside: Prism.languages.javascript
 		},
 		{
-			pattern: /\b(?!await|delete|export|for|if|new|return|switch|throw|typeof|while|yield)(?:[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*\s*)(\([^()]*\))(?=\s*\{)/,
+			pattern: /(\()[^()]+(?=\)\s*=>)/,
+			lookbehind: true,
+			inside: Prism.languages.javascript
+		},
+		{
+			pattern: /(\b(?!await|delete|export|for|if|new|return|switch|throw|typeof|while|yield)(?:[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*\s*)\(\s*)\S[^()]*(?=\s*\)\s*\{)/,
+			lookbehind: true,
 			inside: Prism.languages.javascript
 		}
 	],
diff --git a/components/prism-javascript.min.js b/components/prism-javascript.min.js
index 2171167ffa..734d150929 100644
--- a/components/prism-javascript.min.js
+++ b/components/prism-javascript.min.js
@@ -1 +1 @@
-Prism.languages.javascript=Prism.languages.extend("clike",{keyword:/\b(?:as|async|await|break|case|catch|class|const|continue|debugger|default|delete|do|else|enum|export|extends|finally|for|from|function|get|if|implements|import|in|instanceof|interface|let|new|null|of|package|private|protected|public|return|set|static|super|switch|this|throw|try|typeof|var|void|while|with|yield)\b/,number:/\b(?:0[xX][\dA-Fa-f]+|0[bB][01]+|0[oO][0-7]+|NaN|Infinity)\b|(?:\b\d+\.?\d*|\B\.\d+)(?:[Ee][+-]?\d+)?/,"function":/[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*(?=\s*\()/i,operator:/-[-=]?|\+[+=]?|!=?=?|<<?=?|>>?>?=?|=(?:==?|>)?|&[&=]?|\|[|=]?|\*\*?=?|\/=?|~|\^=?|%=?|\?|\.{3}/}),Prism.languages.insertBefore("javascript","keyword",{regex:{pattern:/((?:^|[^$\w\xA0-\uFFFF."'\])\s])\s*)\/(\[[^\]\r\n]+]|\\.|[^\/\\\[\r\n])+\/[gimyu]{0,5}(?=\s*($|[\r\n,.;})\]]))/,lookbehind:!0,greedy:!0},"function-variable":{pattern:/[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*(?=\s*=\s*(?:async(?:(?:\s*(?=\())|\s+))?(?:function\b|(?:\([^()]*\)|[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)\s*=>))/i,alias:"function"},parameter:[{pattern:/(function)(?:\s+[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)?\s*(\([^()]*\))/,lookbehind:!0,inside:Prism.languages.javascript},{pattern:/(\([^()]*\)|[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)(?=\s*=>)/,inside:Prism.languages.javascript},{pattern:/\b(?!await|delete|export|for|if|new|return|switch|throw|typeof|while|yield)(?:[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*\s*)(\([^()]*\))(?=\s*\{)/,inside:Prism.languages.javascript}],constant:/\b[A-Z][A-Z\d_]*\b/}),Prism.languages.insertBefore("javascript","string",{"template-string":{pattern:/`(?:\\[\s\S]|\${[^}]+}|[^\\`])*`/,greedy:!0,inside:{interpolation:{pattern:/\${[^}]+}/,inside:{"interpolation-punctuation":{pattern:/^\${|}$/,alias:"punctuation"},rest:null}},string:/[\s\S]+/}}}),Prism.languages.javascript["template-string"].inside.interpolation.inside.rest=Prism.languages.javascript,Prism.languages.markup&&Prism.languages.insertBefore("markup","tag",{script:{pattern:/(<script[\s\S]*?>)[\s\S]*?(?=<\/script>)/i,lookbehind:!0,inside:Prism.languages.javascript,alias:"language-javascript",greedy:!0}}),Prism.languages.js=Prism.languages.javascript;
\ No newline at end of file
+Prism.languages.javascript=Prism.languages.extend("clike",{keyword:/\b(?:as|async|await|break|case|catch|class|const|continue|debugger|default|delete|do|else|enum|export|extends|finally|for|from|function|get|if|implements|import|in|instanceof|interface|let|new|null|of|package|private|protected|public|return|set|static|super|switch|this|throw|try|typeof|var|void|while|with|yield)\b/,number:/\b(?:0[xX][\dA-Fa-f]+|0[bB][01]+|0[oO][0-7]+|NaN|Infinity)\b|(?:\b\d+\.?\d*|\B\.\d+)(?:[Ee][+-]?\d+)?/,"function":/[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*(?=\s*\()/i,operator:/-[-=]?|\+[+=]?|!=?=?|<<?=?|>>?>?=?|=(?:==?|>)?|&[&=]?|\|[|=]?|\*\*?=?|\/=?|~|\^=?|%=?|\?|\.{3}/}),Prism.languages.insertBefore("javascript","keyword",{regex:{pattern:/((?:^|[^$\w\xA0-\uFFFF."'\])\s])\s*)\/(\[[^\]\r\n]+]|\\.|[^\/\\\[\r\n])+\/[gimyu]{0,5}(?=\s*($|[\r\n,.;})\]]))/,lookbehind:!0,greedy:!0},"function-variable":{pattern:/[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*(?=\s*=\s*(?:async(?:(?:\s*(?=\())|\s+))?(?:function\b|(?:\([^()]*\)|[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)\s*=>))/i,alias:"function"},parameter:[{pattern:/(function(?:\s+[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)?\s*\(\s*)\S[^()]*(?=\s*\))/,lookbehind:!0,inside:Prism.languages.javascript},{pattern:/[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*(?=\s*=>)/,inside:Prism.languages.javascript},{pattern:/(\()[^()]+(?=\)\s*=>)/,lookbehind:!0,inside:Prism.languages.javascript},{pattern:/(\b(?!await|delete|export|for|if|new|return|switch|throw|typeof|while|yield)(?:[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*\s*)\(\s*)\S[^()]*(?=\s*\)\s*\{)/,lookbehind:!0,inside:Prism.languages.javascript}],constant:/\b[A-Z][A-Z\d_]*\b/}),Prism.languages.insertBefore("javascript","string",{"template-string":{pattern:/`(?:\\[\s\S]|\${[^}]+}|[^\\`])*`/,greedy:!0,inside:{interpolation:{pattern:/\${[^}]+}/,inside:{"interpolation-punctuation":{pattern:/^\${|}$/,alias:"punctuation"},rest:null}},string:/[\s\S]+/}}}),Prism.languages.javascript["template-string"].inside.interpolation.inside.rest=Prism.languages.javascript,Prism.languages.markup&&Prism.languages.insertBefore("markup","tag",{script:{pattern:/(<script[\s\S]*?>)[\s\S]*?(?=<\/script>)/i,lookbehind:!0,inside:Prism.languages.javascript,alias:"language-javascript",greedy:!0}}),Prism.languages.js=Prism.languages.javascript;
\ No newline at end of file
diff --git a/prism.js b/prism.js
index 893b01961b..0b58a69534 100644
--- a/prism.js
+++ b/prism.js
@@ -742,16 +742,22 @@ Prism.languages.insertBefore('javascript', 'keyword', {
 	},
 	'parameter': [
 		{
-			pattern: /(function)(?:\s+[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)?\s*(\([^()]*\))/,
+			pattern: /(function(?:\s+[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)?\s*\(\s*)\S[^()]*(?=\s*\))/,
 			lookbehind: true,
 			inside: Prism.languages.javascript
 		},
 		{
-			pattern: /(\([^()]*\)|[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*)(?=\s*=>)/,
+			pattern: /[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*(?=\s*=>)/,
 			inside: Prism.languages.javascript
 		},
 		{
-			pattern: /\b(?!await|delete|export|for|if|new|return|switch|throw|typeof|while|yield)(?:[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*\s*)(\([^()]*\))(?=\s*\{)/,
+			pattern: /(\()[^()]+(?=\)\s*=>)/,
+			lookbehind: true,
+			inside: Prism.languages.javascript
+		},
+		{
+			pattern: /(\b(?!await|delete|export|for|if|new|return|switch|throw|typeof|while|yield)(?:[_$a-z\xA0-\uFFFF][$\w\xA0-\uFFFF]*\s*)\(\s*)\S[^()]*(?=\s*\)\s*\{)/,
+			lookbehind: true,
 			inside: Prism.languages.javascript
 		}
 	],
diff --git a/tests/languages/javascript/class-method_feature.test b/tests/languages/javascript/class-method_feature.test
index 01180d4238..a2e3ceaa7e 100644
--- a/tests/languages/javascript/class-method_feature.test
+++ b/tests/languages/javascript/class-method_feature.test
@@ -11,38 +11,36 @@ class Test {
 	["class-name", ["Test"]],
 	["punctuation", "{"],
 
+	["function", "foo"],
+	["punctuation", "("],
 	["parameter", [
-		["function", "foo"],
-		["punctuation", "("],
 		"x",
 		["punctuation", ","],
 		" y ",
 		["operator", "="],
-		["number", "0"],
-		["punctuation", ")"]
+		["number", "0"]
 	]],
+	["punctuation", ")"],
 	["punctuation", "{"],
 	["punctuation", "}"],
 
 	["keyword", "async"],
+	["function", "bar"],
+	["punctuation", "("],
 	["parameter", [
-		["function", "bar"],
-		["punctuation", "("],
 		"x",
 		["punctuation", ","],
 		" y ",
 		["operator", "="],
-		["number", "0"],
-		["punctuation", ")"]
+		["number", "0"]
 	]],
+	["punctuation", ")"],
 	["punctuation", "{"],
 	["punctuation", "}"],
 
-	["parameter", [
-		["function", "_"],
-		["punctuation", "("],
-		["punctuation", ")"]
-	]],
+	["function", "_"],
+	["punctuation", "("],
+	["punctuation", ")"],
 	["punctuation", "{"],
 	["punctuation", "}"],
 
diff --git a/tests/languages/javascript/function-variable_feature.test b/tests/languages/javascript/function-variable_feature.test
index 12df6f5b3a..8dbeb0aae8 100644
--- a/tests/languages/javascript/function-variable_feature.test
+++ b/tests/languages/javascript/function-variable_feature.test
@@ -12,13 +12,13 @@ fooBar = (x, y) => x
 	["function-variable", "foo"],
 	["operator", "="],
 	["keyword", "function"],
+	["punctuation", "("],
 	["parameter", [
-		["punctuation", "("],
-		" x",
+		"x",
 		["punctuation", ","],
-		" y",
-		["punctuation", ")"]
+		" y"
 	]],
+	["punctuation", ")"],
 	["punctuation", "{"],
 	["punctuation", "}"],
 
@@ -26,23 +26,23 @@ fooBar = (x, y) => x
 	["operator", "="],
 	["keyword", "async"],
 	["keyword", "function"],
+	["function", "baz"],
+	["punctuation", "("],
 	["parameter", [
-		["function", "baz"],
-		["punctuation", "("],
-		"x ",
-		["punctuation", ")"]
+		"x "
 	]],
+	["punctuation", ")"],
 	["punctuation", "{"],
 	["punctuation", "}"],
 
 	["function-variable", "baz"],
 	["operator", "="],
 	["keyword", "async"],
+	["punctuation", "("],
 	["parameter", [
-		["punctuation", "("],
-		"x",
-		["punctuation", ")"]
+		"x"
 	]],
+	["punctuation", ")"],
 	["operator", "=>"], " x\r\n",
 
 	["function-variable", "fooBar"],
@@ -54,21 +54,19 @@ fooBar = (x, y) => x
 
 	["function-variable", "fooBar"],
 	["operator", "="],
+	["punctuation", "("],
 	["parameter", [
-		["punctuation", "("],
 		"x",
 		["punctuation", ","],
-		" y",
-		["punctuation", ")"]
+		" y"
 	]],
+	["punctuation", ")"],
 	["operator", "=>"], " x\r\n",
 
 	["function-variable", "ಠ_ಠ"],
 	["operator", "="],
-	["parameter", [
-		["punctuation", "("],
-		["punctuation", ")"]
-	]],
+	["punctuation", "("],
+	["punctuation", ")"],
 	["operator", "=>"],
 	["punctuation", "{"],
 	["punctuation", "}"],
@@ -76,15 +74,15 @@ fooBar = (x, y) => x
 	["function-variable", "Ƞȡ_҇"],
 	["operator", "="],
 	["keyword", "async"],
+	["punctuation", "("],
 	["parameter", [
-		["punctuation", "("],
 		"ಠ",
 		["punctuation", ","],
 		" Ƞ ",
 		["operator", "="],
-		["number", "2"],
-		["punctuation", ")"]
+		["number", "2"]
 	]],
+	["punctuation", ")"],
 	["operator", "=>"],
 	["punctuation", "{"],
 	["punctuation", "}"]
diff --git a/tests/languages/jsx/issue1294.test b/tests/languages/jsx/issue1294.test
index a8b6dbe106..4d167f146c 100644
--- a/tests/languages/jsx/issue1294.test
+++ b/tests/languages/jsx/issue1294.test
@@ -13,7 +13,8 @@ export default () => (
 [
 	["keyword", "export"],
 	["keyword", "default"],
-	["parameter", [["punctuation", "("], ["punctuation", ")"]]],
+	["punctuation", "("],
+	["punctuation", ")"],
 	["operator", "=>"], ["punctuation", "("],
 	["tag", [
 		["tag", [
diff --git a/tests/languages/jsx/issue1335.test b/tests/languages/jsx/issue1335.test
index bc5bd6fc16..a420215d08 100644
--- a/tests/languages/jsx/issue1335.test
+++ b/tests/languages/jsx/issue1335.test
@@ -20,11 +20,11 @@
 		["script", [
 			["script-punctuation", "="],
 			["punctuation", "{"],
+			["punctuation", "("],
 			["parameter", [
-				["punctuation", "("],
-				"e",
-				["punctuation", ")"]
+				"e"
 			]],
+			["punctuation", ")"],
 			["operator", "=>"],
 			["keyword", "this"],
 			["punctuation", "."],
diff --git a/tests/languages/jsx/issue1421.test b/tests/languages/jsx/issue1421.test
index 43c2f14ea6..e74f14b002 100644
--- a/tests/languages/jsx/issue1421.test
+++ b/tests/languages/jsx/issue1421.test
@@ -17,10 +17,8 @@ class Columns extends React.Component {
 	["keyword", "extends"],
 	["class-name", ["React", ["punctuation", "."], "Component"]],
 	["punctuation", "{"],
-	["parameter", [
-		["function", "render"],
-		["punctuation", "("], ["punctuation", ")"]
-	]],
+	["function", "render"],
+	["punctuation", "("], ["punctuation", ")"],
 	["punctuation", "{"],
 	["keyword", "return"], ["punctuation", "("],
 	["tag", [
diff --git a/tests/languages/tsx/tag_feature.test b/tests/languages/tsx/tag_feature.test
index 5c2cf8a154..a881ebbc13 100644
--- a/tests/languages/tsx/tag_feature.test
+++ b/tests/languages/tsx/tag_feature.test
@@ -66,11 +66,9 @@ class Test extends Component {
 	["keyword", "extends"],
 	["class-name", ["Component"]],
 	["punctuation", "{"],
-	["parameter", [
-		["function", "render"],
-		["punctuation", "("],
-		["punctuation", ")"]
-	]],
+	["function", "render"],
+	["punctuation", "("],
+	["punctuation", ")"],
 	["punctuation", "{"],
 	["keyword","return"],
 	["tag", [