perf: replace startsWith with strict equality

packages/commonjs/src/dynamic-modules.js

@@ -36,7 +36,7 @@ export function getDynamicRequireModules(patterns, dynamicRequireRoot) {
   const dynamicRequireModules = new Map();
   const dirNames = new Set();
   for (const pattern of !patterns || Array.isArray(patterns) ? patterns || [] : [patterns]) {
-    const isNegated = pattern.startsWith('!');
+    const isNegated = pattern[0] === '!';
     const modifyMap = (targetPath, resolvedPath) =>
       isNegated
         ? dynamicRequireModules.delete(targetPath)

packages/commonjs/src/resolve-id.js

@@ -120,7 +120,7 @@ export default function getResolveId(extensions, isPossibleCjsId) {
         }
       }
 
-      if (importee.startsWith('\0')) {
+      if (importee[0] === '\0') {
         return null;
       }
 

packages/commonjs/src/resolve-require-sources.js

@@ -164,7 +164,7 @@ export function getRequireResolver(extensions, detectCyclesAndConditional, curre
         const requireTargets = await Promise.all(
           sources.map(async ({ source, isConditional }) => {
             // Never analyze or proxy internal modules
-            if (source.startsWith('\0')) {
+            if (source[0] === '\0') {
               return { id: source, allowProxy: false };
             }
             currentlyResolvingForParent.add(source);

packages/dynamic-import-vars/src/dynamic-import-to-glob.js

@@ -88,13 +88,13 @@ export function dynamicImportToGlob(node, sourceString) {
 
   glob = glob.replace(/\*\*/g, '*');
 
-  if (glob.startsWith('*')) {
+  if (glob[0] === '*') {
     throw new VariableDynamicImportError(
       `invalid import "${sourceString}". It cannot be statically analyzed. Variable dynamic imports must start with ./ and be limited to a specific directory. ${example}`
     );
   }
 
-  if (glob.startsWith('/')) {
+  if (glob[0] === '/') {
     throw new VariableDynamicImportError(
       `invalid import "${sourceString}". Variable absolute imports are not supported, imports must start with ./ in the static part of the import. ${example}`
     );

packages/node-resolve/src/package/resolvePackageImports.ts

@@ -38,7 +38,7 @@ async function resolvePackageImports({
   };
 
   // Assert: specifier begins with "#".
-  if (!importSpecifier.startsWith('#')) {
+  if (importSpecifier[0] !== '#') {
     throw new InvalidModuleSpecifierError(context, true, 'Invalid import specifier.');
   }
 

packages/node-resolve/src/package/utils.ts

@@ -35,7 +35,7 @@ export function isUrl(str: string) {
  * Conditions is an export object where all keys are conditions like 'node' (aka do not with '.')
  */
 export function isConditions(exports: any) {
-  return typeof exports === 'object' && Object.keys(exports).every((k) => !k.startsWith('.'));
+  return typeof exports === 'object' && Object.keys(exports).every((k) => k[0] !== '.');
 }
 
 /**
@@ -50,7 +50,7 @@ export function isMappings(exports: any) {
  */
 export function isMixedExports(exports: Record<string, any>) {
   const keys = Object.keys(exports);
-  return keys.some((k) => k.startsWith('.')) && keys.some((k) => !k.startsWith('.'));
+  return keys.some((k) => k[0] === '.') && keys.some((k) => k[0] !== '.');
 }
 
 export function createBaseErrorMsg(importSpecifier: string, importer: string) {

packages/node-resolve/src/resolveImportSpecifiers.js

@@ -118,7 +118,7 @@ async function resolveWithExportMap({
   ignoreSideEffectsForRoot,
   allowExportsFolderMapping
 }) {
-  if (importSpecifier.startsWith('#')) {
+  if (importSpecifier[0] === '#') {
     // this is a package internal import, resolve using package imports field
     const resolveResult = await resolvePackageImports({
       importSpecifier,

packages/node-resolve/src/util.js

@@ -6,7 +6,7 @@ import { realpathSync } from './fs';
 
 // returns the imported package name for bare module imports
 export function getPackageName(id) {
-  if (id.startsWith('.') || id.startsWith('/')) {
+  if (id[0] === '.' || id[0] === '/') {
     return null;
   }