perf(scripts): hoist regexes

Author: metonym

scripts/build-languages.ts

@@ -2,6 +2,7 @@ import { $ } from "bun";
 import hljs from "highlight.js";
 import type { ModuleNames } from "./build-styles";
 import { createMarkdown } from "./utils/create-markdown";
+import { CONTAINS_DASH, STARTS_WITH_DIGIT } from "./utils/regexes";
 import { toCamelCase } from "./utils/to-camel-case";
 import { writeTo } from "./utils/write-to";
 
@@ -28,8 +29,8 @@ export async function buildLanguages() {
   for (const name of languages) {
     let moduleName = name;
 
-    if (/^[0-9]/.test(name)) moduleName = `_${name}`;
-    if (/-/.test(name)) moduleName = toCamelCase(name);
+    if (STARTS_WITH_DIGIT.test(name)) moduleName = `_${name}`;
+    if (CONTAINS_DASH.test(name)) moduleName = toCamelCase(name);
 
     base += `export { default as ${moduleName} } from './${name}';\n`;
     baseTs += `export declare const ${moduleName}: LanguageType<"${name}">;\n`;

scripts/build-styles.ts

@@ -3,6 +3,13 @@ import { $, Glob } from "bun";
 import { createMarkdown } from "./utils/create-markdown";
 import { postcssScopedStyles } from "./utils/postcss-scoped-styles";
 import { preprocessStyles } from "./utils/preprocess-styles";
+import {
+  BACKTICK,
+  CSS_FILE,
+  DEFAULT_STRING,
+  NON_MINIFIED_CSS,
+  STARTS_WITH_DIGIT,
+} from "./utils/regexes";
 import { toCamelCase } from "./utils/to-camel-case";
 import { writeTo } from "./utils/write-to";
 
@@ -29,11 +36,14 @@ export async function buildStyles() {
 
   for await (const file of glob.scan("node_modules/highlight.js/styles")) {
     const absPath = path.resolve("node_modules/highlight.js/styles", file);
-    if (/(?<!\.min)\.(css)$/.test(file)) {
+    if (NON_MINIFIED_CSS.test(file)) {
       let { name, dir } = path.parse(file);
       let moduleName = toCamelCase(name);
 
-      if (/^[0-9]/.test(moduleName) || /^default$/.test(moduleName)) {
+      if (
+        STARTS_WITH_DIGIT.test(moduleName) ||
+        DEFAULT_STRING.test(moduleName)
+      ) {
         moduleName = `_${moduleName}`;
       }
 
@@ -46,7 +56,7 @@ export async function buildStyles() {
       styles.push({ name, moduleName });
       cssFiles.push({ file, absPath, name, dir, moduleName });
     } else {
-      if (!/\.(css)$/.test(file)) {
+      if (!CSS_FILE.test(file)) {
         copyCommands.push(absPath);
       }
     }
@@ -65,7 +75,7 @@ export async function buildStyles() {
       const cssMinified = preprocessStyles(content, {
         discardComments: "preserve-license",
       });
-      const contentCssForJs = cssMinified.replace(/`/g, "\\`");
+      const contentCssForJs = cssMinified.replace(BACKTICK, "\\`");
 
       const exportee = `const ${moduleName} = \`<style>${contentCssForJs}</style>\`;\n
       export default ${moduleName};\n`;

scripts/utils/postcss-scoped-styles.ts

@@ -1,4 +1,5 @@
 import type { Plugin } from "postcss";
+import { PRE_SELECTOR } from "./regexes";
 
 /**
  * Scopes CSS selectors to a given module name.
@@ -16,8 +17,8 @@ export const postcssScopedStyles = (moduleName: string): Plugin => {
     Once(root) {
       root.walkRules((rule) => {
         rule.selectors = rule.selectors.map((selector) => {
-          if (/^pre /.test(selector)) {
-            selector = `pre.${moduleName}${selector.replace(/^pre /, " ")}`;
+          if (PRE_SELECTOR.test(selector)) {
+            selector = `pre.${moduleName}${selector.replace(PRE_SELECTOR, " ")}`;
           } else {
             selector = `.${moduleName} ${selector}`;
           }

scripts/utils/preprocess-styles.ts

@@ -4,6 +4,7 @@ import postcss, { type Plugin } from "postcss";
 import discardDuplicates from "postcss-discard-duplicates";
 import { inlineCssVars } from "postcss-inline-css-vars";
 import mergeRules from "postcss-merge-rules";
+import { LICENSE_OR_AUTHOR } from "./regexes";
 
 /**
  * Raw styles from `highlight.js` are preprocessed for consistency.
@@ -32,7 +33,7 @@ export const preprocessStyles = (
           options?.discardComments === "preserve-license"
             ? {
                 remove: (comment) => {
-                  if (/(License|Author)/i.test(comment)) {
+                  if (LICENSE_OR_AUTHOR.test(comment)) {
                     // Preserve license comments.
                     return false;
                   }

scripts/utils/regexes.ts

@@ -0,0 +1,45 @@
+/**
+ * Shared regex patterns used across build scripts
+ */
+
+/** Matches strings that start with a digit */
+export const STARTS_WITH_DIGIT = /^[0-9]/;
+
+/** Matches strings containing a dash */
+export const CONTAINS_DASH = /-/;
+
+/** Matches CSS files that are not minified (negative lookbehind for .min) */
+export const NON_MINIFIED_CSS = /(?<!\.min)\.(css)$/;
+
+/** Matches CSS files */
+export const CSS_FILE = /\.(css)$/;
+
+/** Matches the exact string "default" */
+export const DEFAULT_STRING = /^default$/;
+
+/** Matches backticks (for escaping in template literals) */
+export const BACKTICK = /`/g;
+
+/** Matches dash or period (for splitting strings) */
+export const DASH_OR_PERIOD = /-|\./g;
+
+/** Matches "License" or "Author" (case insensitive) */
+export const LICENSE_OR_AUTHOR = /(License|Author)/i;
+
+/** Matches selectors starting with "pre " */
+export const PRE_SELECTOR = /^pre /;
+
+/** Matches Windows line endings (CRLF) */
+export const WINDOWS_LINE_ENDING = /\r\n/g;
+
+/** Matches trailing spaces or tabs at the end of lines */
+export const TRAILING_WHITESPACE = /[ \t]+$/gm;
+
+/** Matches leading newlines at the start of a string */
+export const LEADING_NEWLINES = /^\n+/;
+
+/** Matches 3 or more consecutive newlines */
+export const MULTIPLE_NEWLINES = /\n{3,}/g;
+
+/** Matches trailing newlines at the end of a string */
+export const TRAILING_NEWLINES = /\n*$/;

scripts/utils/to-camel-case.ts

@@ -1,3 +1,5 @@
+import { DASH_OR_PERIOD } from "./regexes";
+
 /**
  * Converts a dash/period separated string into pascal case
  * @example
@@ -6,7 +8,7 @@
  */
 export const toCamelCase = (str: string) =>
   str
-    .split(new RegExp(/-|\./g))
+    .split(DASH_OR_PERIOD)
     .map((fragment, index) => {
       if (index === 0) return fragment;
       return [fragment.slice(0, 1).toUpperCase(), fragment.slice(1)].join("");

scripts/utils/write-to.ts

@@ -1,18 +1,26 @@
+import {
+  LEADING_NEWLINES,
+  MULTIPLE_NEWLINES,
+  TRAILING_NEWLINES,
+  TRAILING_WHITESPACE,
+  WINDOWS_LINE_ENDING,
+} from "./regexes";
+
 function formatMarkdown(content: string): string {
   // Normalize line endings
-  let formatted = content.replace(/\r\n/g, "\n");
+  let formatted = content.replace(WINDOWS_LINE_ENDING, "\n");
 
   // Remove trailing whitespace from each line
-  formatted = formatted.replace(/[ \t]+$/gm, "");
+  formatted = formatted.replace(TRAILING_WHITESPACE, "");
 
   // Remove leading blank lines
-  formatted = formatted.replace(/^\n+/, "");
+  formatted = formatted.replace(LEADING_NEWLINES, "");
 
   // Normalize blank lines: collapse 3+ consecutive newlines into exactly 2 newlines (one blank line)
-  formatted = formatted.replace(/\n{3,}/g, "\n\n");
+  formatted = formatted.replace(MULTIPLE_NEWLINES, "\n\n");
 
   // Ensure file ends with single newline
-  formatted = formatted.replace(/\n*$/, "\n");
+  formatted = formatted.replace(TRAILING_NEWLINES, "\n");
 
   return formatted;
 }