util: add getSystemErrorMap() impl

eladkishon · jasnell · commit 802171057f33 · 2021-04-13T08:44:26.000-07:00
PR-URL: #38101 Fixes: #37951 Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com> Reviewed-By: Darshan Sen <raisinten@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/doc/api/util.md b/doc/api/util.md
@@ -376,6 +376,25 @@ fs.access('file/that/does/not/exist', (err) => {
 });
 ```
 
+## `util.getSystemErrorMap()`
+<!-- YAML
+added: REPLACEME
+-->
+
+* Returns: {Map}
+
+Returns a Map of all system error codes available from the Node.js API.
+The mapping between error codes and error names is platform-dependent.
+See [Common System Errors][] for the names of common errors.
+
+```js
+fs.access('file/that/does/not/exist', (err) => {
+  const errorMap = util.getSystemErrorMap();
+  const name = errorMap.get(err.errno);
+  console.error(name);  // ENOENT
+});
+```
+
 ## `util.inherits(constructor, superConstructor)`
 <!-- YAML
 added: v0.3.0
diff --git a/lib/internal/util.js b/lib/internal/util.js
@@ -53,6 +53,13 @@ const experimentalWarnings = new SafeSet();
 
 const colorRegExp = /\u001b\[\d\d?m/g; // eslint-disable-line no-control-regex
 
+let uvBinding;
+
+function lazyUv() {
+  uvBinding ??= internalBinding('uv');
+  return uvBinding;
+}
+
 function removeColors(str) {
   return StringPrototypeReplace(str, colorRegExp, '');
 }
@@ -286,6 +293,10 @@ function getSystemErrorName(err) {
   return entry ? entry[0] : `Unknown system error ${err}`;
 }
 
+function getSystemErrorMap() {
+  return lazyUv().getErrorMap();
+}
+
 const kCustomPromisifiedSymbol = SymbolFor('nodejs.util.promisify.custom');
 const kCustomPromisifyArgsSymbol = Symbol('customPromisifyArgs');
 
@@ -442,6 +453,7 @@ module.exports = {
   emitExperimentalWarning,
   filterDuplicateStrings,
   getConstructorOf,
+  getSystemErrorMap,
   getSystemErrorName,
   isError,
   isInsideNodeModules,
diff --git a/lib/util.js b/lib/util.js
@@ -67,6 +67,7 @@ const types = require('internal/util/types');
 
 const {
   deprecate,
+  getSystemErrorMap,
   getSystemErrorName: internalErrorName,
   promisify
 } = require('internal/util');
@@ -256,6 +257,7 @@ module.exports = {
   deprecate,
   format,
   formatWithOptions,
+  getSystemErrorMap,
   getSystemErrorName,
   inherits,
   inspect,
diff --git a/test/parallel/test-uv-errmap.js b/test/parallel/test-uv-errmap.js
@@ -0,0 +1,24 @@
+// Flags: --expose-internals
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const {
+  getSystemErrorMap,
+  _errnoException
+} = require('util');
+
+const { internalBinding } = require('internal/test/binding');
+const uv = internalBinding('uv');
+const uvKeys = Object.keys(uv);
+
+const errMap = getSystemErrorMap();
+
+uvKeys.forEach((key) => {
+  if (!key.startsWith('UV_'))
+    return;
+
+  const err = _errnoException(uv[key]);
+  const name = uv.errname(uv[key]);
+  assert.strictEqual(errMap.get(err.errno)[0], name);
+});
