errors: implement new error handling

This implements a function based system. Instead of passing in the error code as first argument, the error code itself is a error class. It already contains the correct error type, so while adding a new error no one has to think about the error type anymore. In case a single error code has more than one error type, the error class has properties for the non default error types. Those can be used as fallback. This prevents typos, makes the implementation easier and it is less verbose when writing the code for a new error. The implementation itself does not interfere with the old implementation. So the old and the new system can co-exist and it is possible to slowly migrate the old ones to the new system. PR-URL: #18857 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Gus Caplan <me@gus.host> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
nodejs · BridgeAR · Feb 6, 2018 · Feb 9, 2018 · Feb 10, 2018 · Feb 12, 2018
commit cc63116880cd7f4d39bdc527a9b9f3073f983af0
diff --git a/lib/internal/errors.js b/lib/internal/errors.js
@@ -12,6 +12,7 @@
 
 const kCode = Symbol('code');
 const messages = new Map();
+const codes = {};
 
 var green = '';
 var red = '';
@@ -194,6 +195,54 @@ function createErrDiff(actual, expected, operator) {
   return `${msg}${skipped ? skippedMsg : ''}\n${res}${other}${end}`;
 }
 
+function makeNodeErrorWithCode(Base, key) {
+  return class NodeError extends Base {
+    constructor(...args) {
+      super(message(key, args));
+    }
+
+    get name() {
+      return `${super.name} [${key}]`;
+    }
+
+    set name(value) {
+      defineProperty(this, 'name', {
+        configurable: true,
+        enumerable: true,
+        value,
+        writable: true
+      });
+    }
+
+    get code() {
+      return key;
+    }
+
+    set code(value) {
+      defineProperty(this, 'code', {
+        configurable: true,
+        enumerable: true,
+        value,
+        writable: true
+      });
+    }
+  };
+}
+
+// Utility function for registering the error codes. Only used here. Exported
+// *only* to allow for testing.
+function E(sym, val, def, ...otherClasses) {
+  messages.set(sym, val);
+  if (def === undefined) return;
+  def = makeNodeErrorWithCode(def, sym);
+  if (otherClasses.length !== 0) {
+    otherClasses.forEach((clazz) => {
+      def[clazz.name] = makeNodeErrorWithCode(clazz, sym);
+    });
+  }
+  codes[sym] = def;
+}
+
 class AssertionError extends Error {
   constructor(options) {
     if (typeof options !== 'object' || options === null) {
@@ -296,12 +345,6 @@ function message(key, args) {
   return String(fmt.apply(null, args));
 }
 
-// Utility function for registering the error codes. Only used here. Exported
-// *only* to allow for testing.
-function E(sym, val) {
-  messages.set(sym, typeof val === 'function' ? val : String(val));
-}
-
 /**
  * This used to be util._errnoException().
  *
@@ -412,6 +455,7 @@ module.exports = exports = {
   RangeError: makeNodeError(RangeError),
   URIError: makeNodeError(URIError),
   AssertionError,
+  codes,
   E // This is exported only to facilitate testing.
 };