refactor: avoid redundant buffer to string

Author: antongolub

.size-limit.json

@@ -9,7 +9,7 @@
   {
     "name": "zx/index",
     "path": "build/*.{js,cjs}",
-    "limit": "809 kB",
+    "limit": "810 kB",
     "brotli": false,
     "gzip": false
   },

src/cli.ts

@@ -30,7 +30,7 @@ import {
 } from './index.js'
 import { installDeps, parseDeps } from './deps.js'
 import { startRepl } from './repl.js'
-import { randomId } from './util.js'
+import { randomId, bufToString } from './util.js'
 import { createRequire } from './vendor.js'
 
 const EXT = '.mjs'
@@ -189,7 +189,7 @@ export async function importPath(
   filepath: string,
   origin = filepath
 ): Promise<void> {
-  const contents = await fs.readFile(filepath)
+  const contents = await fs.readFile(filepath, 'utf8')
   const { ext, base, dir } = path.parse(filepath)
   const tempFilename = getFilepath(dir, base)
 
@@ -224,7 +224,7 @@ export function transformMarkdown(buf: Buffer | string): string {
   let state = 'root'
   let codeBlockEnd = ''
   let prevLineIsEmpty = true
-  for (const line of buf.toString().split(/\r?\n/)) {
+  for (const line of bufToString(buf).split(/\r?\n/)) {
     switch (state) {
       case 'root':
         if (tabRe.test(line) && prevLineIsEmpty) {

src/core.ts

@@ -47,6 +47,8 @@ import {
   log,
   isString,
   isStringLiteral,
+  bufToString,
+  getLast,
   noop,
   once,
   parseBool,
@@ -64,6 +66,7 @@ export { log, type LogEntry } from './util.js'
 const CWD = Symbol('processCwd')
 const SYNC = Symbol('syncExec')
 const EOL = Buffer.from(_EOL)
+const BR_CC = '\n'.charCodeAt(0)
 const SIGTERM = 'SIGTERM'
 const ENV_PREFIX = 'ZX_'
 const storage = new AsyncLocalStorage<Options>()
@@ -330,8 +333,8 @@ export class ProcessPromise extends Promise<ProcessOutput> {
           }
 
           // Ensures EOL
-          if (stdout.length && !stdout[stdout.length - 1]!.toString().endsWith('\n')) c.on.stdout!(EOL, c)
-          if (stderr.length && !stderr[stderr.length - 1]!.toString().endsWith('\n')) c.on.stderr!(EOL, c)
+          if (stdout.length && getLast(getLast(stdout)) !== BR_CC) c.on.stdout!(EOL, c)
+          if (stderr.length && getLast(getLast(stderr)) !== BR_CC) c.on.stderr!(EOL, c)
 
           $.log({ kind: 'end', signal, exitCode: status, duration, error, verbose: self.isVerbose(), id })
           const output = self._output = new ProcessOutput(dto)
@@ -598,7 +601,7 @@ export class ProcessPromise extends Promise<ProcessOutput> {
   async *[Symbol.asyncIterator]() {
     let last: string | undefined
     const getLines = (chunk: Buffer | string) => {
-      const lines = ((last || '') + chunk.toString()).split('\n')
+      const lines = ((last || '') + bufToString(chunk)).split('\n')
       last = lines.pop()
       return lines
     }

src/deps.ts

@@ -102,8 +102,8 @@ const builtins = new Set([
 const nameRe = /^(?<name>(@[a-z\d-~][\w-.~]*\/)?[a-z\d-~][\w-.~]*)\/?.*$/i
 const versionRe = /^@(?<version>[~^]?(v?[\dx*]+([-.][\d*a-z-]+)*))/i
 
-export function parseDeps(content: Buffer | string): Record<string, string> {
-  return depseek(content.toString() + '\n', { comments: true }).reduce<
+export function parseDeps(content: string): Record<string, string> {
+  return depseek(content + '\n', { comments: true }).reduce<
     Record<string, string>
   >((m, { type, value }, i, list) => {
     if (type === 'dep') {

src/util.ts

@@ -59,6 +59,13 @@ export function isString(obj: any) {
   return typeof obj === 'string'
 }
 
+const utf8Decoder = new TextDecoder('utf-8')
+export const bufToString = (buf: Buffer | string): string =>
+  isString(buf) ? buf : utf8Decoder.decode(buf)
+
+export const getLast = <T>(arr: { length: number; [i: number]: any }): T =>
+  arr[arr.length - 1]
+
 const pad = (v: string) => (v === ' ' ? ' ' : '')
 
 export function preferLocalBin(