lib: call normalizeEncoding in fs.writeFileSync and fs.readFileSync

Author: JonasBa

benchmark-results-before.txt

@@ -0,0 +1,12 @@
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=1024 useFd="true" encoding="utf8": 379,308.70987625053
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=102400 useFd="true" encoding="utf8": 52,849.46896325091
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=1048576 useFd="true" encoding="utf8": 6,754.315163099825
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=1024 useFd="false" encoding="utf8": 18,715.011934282385
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=102400 useFd="false" encoding="utf8": 13,563.337333477992
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=1048576 useFd="false" encoding="utf8": 3,315.224384265696
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=1024 useFd="true" encoding="UTF8": 259,456.6769619076
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=102400 useFd="true" encoding="UTF8": 11,036.740891030086
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=1048576 useFd="true" encoding="UTF8": 1,157.094808334633
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=1024 useFd="false" encoding="UTF8": 17,446.90688149625
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=102400 useFd="false" encoding="UTF8": 7,024.340216894065
+fs/bench-writeFileSync.js n=1000 func="writeFile" useBuffer="false" length=1048576 useFd="false" encoding="UTF8": 1,024.8417373799266

benchmark/fs/bench-writeFileSync.js

@@ -7,7 +7,7 @@ tmpdir.refresh();
 
 // Some variants are commented out as they do not show a change and just slow
 const bench = common.createBenchmark(main, {
-  encoding: ['utf8'],
+  encoding: ['utf8', 'UTF8'],
   useFd: ['true', 'false'],
   length: [1024, 102400, 1024 * 1024],
 

lib/fs.js

@@ -60,6 +60,8 @@ const {
 
 const pathModule = require('path');
 const { isAbsolute } = pathModule;
+
+const { normalizeEncoding } = require('internal/util');
 const { isArrayBufferView } = require('internal/util/types');
 
 const binding = internalBinding('fs');
@@ -428,7 +430,7 @@ function tryReadSync(fd, isUserFd, buffer, pos, len) {
 function readFileSync(path, options) {
   options = getOptions(options, { flag: 'r' });
 
-  if (options.encoding === 'utf8' || options.encoding === 'utf-8') {
+  if (normalizeEncoding(options.encoding) === 'utf8') {
     if (!isInt32(path)) {
       path = getValidatedPath(path);
     }
@@ -2383,7 +2385,7 @@ function writeFileSync(path, data, options) {
   const flag = options.flag || 'w';
 
   // C++ fast path for string data and UTF8 encoding
-  if (typeof data === 'string' && (options.encoding === 'utf8' || options.encoding === 'utf-8')) {
+  if (typeof data === 'string' && normalizeEncoding(options.encoding) === 'utf8') {
     if (!isInt32(path)) {
       path = getValidatedPath(path);
     }