diff --git a/src/cli/usage.js b/src/cli/usage.js
index 21a66f34c..9ba5ab599 100644
--- a/src/cli/usage.js
+++ b/src/cli/usage.js
@@ -73,9 +73,7 @@ function createChoiceUsages(choices, margin, indentation) {
     (choice) => !choice.deprecated && choice.since !== null
   );
   const threshold =
-    activeChoices
-      .map((choice) => choice.value.length)
-      .reduce((current, length) => Math.max(current, length), 0) + margin;
+    Math.max(0, ...activeChoices.map((choice) => choice.value.length)) + margin;
   return activeChoices.map((choice) =>
     indent(
       createOptionUsageRow(choice.value, choice.description, threshold),
diff --git a/src/language-html/print-preprocess.js b/src/language-html/print-preprocess.js
index 041db5c58..c6438f1d9 100644
--- a/src/language-html/print-preprocess.js
+++ b/src/language-html/print-preprocess.js
@@ -303,8 +303,8 @@ function extractInterpolation(ast, options) {
  * - add `isWhitespaceSensitive`, `isIndentationSensitive` field for text nodes
  * - remove insensitive whitespaces
  */
+const WHITESPACE_NODE = { type: "whitespace" };
 function extractWhitespaces(ast /*, options*/) {
-  const TYPE_WHITESPACE = "whitespace";
   return ast.map((node) => {
     if (!node.children) {
       return node;
@@ -330,9 +330,9 @@ function extractWhitespaces(ast /*, options*/) {
       isIndentationSensitive,
       children: node.children
         // extract whitespace nodes
-        .reduce((newChildren, child) => {
+        .flatMap((child) => {
           if (child.type !== "text" || isWhitespaceSensitive) {
-            return [...newChildren, child];
+            return child;
           }
 
           const localChildren = [];
@@ -341,7 +341,7 @@ function extractWhitespaces(ast /*, options*/) {
             getLeadingAndTrailingHtmlWhitespace(child.value);
 
           if (leadingWhitespace) {
-            localChildren.push({ type: TYPE_WHITESPACE });
+            localChildren.push(WHITESPACE_NODE);
           }
 
           if (text) {
@@ -356,32 +356,25 @@ function extractWhitespaces(ast /*, options*/) {
           }
 
           if (trailingWhitespace) {
-            localChildren.push({ type: TYPE_WHITESPACE });
+            localChildren.push(WHITESPACE_NODE);
           }
 
-          return [...newChildren, ...localChildren];
-        }, [])
-        // set hasLeadingSpaces/hasTrailingSpaces and filter whitespace nodes
-        .reduce((newChildren, child, i, children) => {
-          if (child.type === TYPE_WHITESPACE) {
-            return newChildren;
+          return localChildren;
+        })
+        // set hasLeadingSpaces/hasTrailingSpaces
+        .map((child, index, children) => {
+          if (child === WHITESPACE_NODE) {
+            return;
           }
 
-          const hasLeadingSpaces =
-            i !== 0 && children[i - 1].type === TYPE_WHITESPACE;
-          const hasTrailingSpaces =
-            i !== children.length - 1 &&
-            children[i + 1].type === TYPE_WHITESPACE;
-
-          return [
-            ...newChildren,
-            {
-              ...child,
-              hasLeadingSpaces,
-              hasTrailingSpaces,
-            },
-          ];
-        }, []),
+          return {
+            ...child,
+            hasLeadingSpaces: children[index - 1] === WHITESPACE_NODE,
+            hasTrailingSpaces: children[index + 1] === WHITESPACE_NODE,
+          };
+        })
+        // filter whitespace nodes
+        .filter(Boolean),
     });
   });
 }
diff --git a/src/main/parser.js b/src/main/parser.js
index 499e1c4ad..9ce082873 100644
--- a/src/main/parser.js
+++ b/src/main/parser.js
@@ -69,15 +69,19 @@ function parse(text, opts) {
 
   // Create a new object {parserName: parseFn}. Uses defineProperty() to only call
   // the parsers getters when actually calling the parser `parse` function.
-  const parsersForCustomParserApi = Object.keys(parsers).reduce(
-    (object, parserName) =>
-      Object.defineProperty(object, parserName, {
-        enumerable: true,
-        get() {
-          return parsers[parserName].parse;
+  const parsersForCustomParserApi = Object.defineProperties(
+    {},
+    Object.fromEntries(
+      Object.keys(parsers).map((parserName) => [
+        parserName,
+        {
+          enumerable: true,
+          get() {
+            return parsers[parserName].parse;
+          },
         },
-      }),
-    {}
+      ])
+    )
   );
 
   const parser = resolveParser(opts, parsers);
diff --git a/src/main/support.js b/src/main/support.js
index f3548b5c6..8e0a85016 100644
--- a/src/main/support.js
+++ b/src/main/support.js
@@ -30,7 +30,7 @@ function getSupportInfo({
   const version = currentVersion.split("-", 1)[0];
 
   const languages = plugins
-    .reduce((all, plugin) => [...all, ...(plugin.languages || [])], [])
+    .flatMap((plugin) => plugin.languages || [])
     .filter(filterSince);
 
   const options = arrayify(