assert: DRY .throws code

This refactors some code for less duplication.
Backport-PR-URL: #31431
PR-URL: #28263
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: BridgeAR

lib/assert.js

@@ -25,6 +25,7 @@ const {
  ObjectAssign,
  ObjectIs,
  ObjectKeys,
+ ObjectPrototypeIsPrototypeOf,
  Map,
 }=primordials;
 
@@ -571,6 +572,9 @@ function compareExceptionKey(actual, expected, key, message, keys, fn) {
 }
 
 functionexpectedException(actual,expected,message,fn){
+letgeneratedMessage=false;
+letthrowError=false;
+
 if(typeofexpected!=='function'){
 // Handle regular expressions.
 if(isRegExp(expected)){
@@ -583,20 +587,9 @@ function expectedException(actual, expected, message, fn) {
 message='The input did not match the regular expression '+
 `${inspect(expected)}. Input:\n\n${inspect(str)}\n`;
 }
-
-consterr=newAssertionError({
- actual,
- expected,
- message,
-operator: fn.name,
-stackStartFn: fn
-});
-err.generatedMessage=generatedMessage;
-throwerr;
-}
-
-// Handle primitives properly.
-if(typeofactual!=='object'||actual===null){
+throwError=true;
+// Handle primitives properly.
+}elseif(typeofactual!=='object'||actual===null){
 consterr=newAssertionError({
  actual,
  expected,
@@ -606,43 +599,52 @@ function expectedException(actual, expected, message, fn) {
 });
 err.operator=fn.name;
 throwerr;
-}
-
-// Handle validation objects.
-constkeys=ObjectKeys(expected);
-// Special handle errors to make sure the name and the message are compared
-// as well.
-if(expectedinstanceofError){
-keys.push('name','message');
-}elseif(keys.length===0){
-thrownewERR_INVALID_ARG_VALUE('error',
-expected,'may not be an empty object');
-}
-if(isDeepEqual===undefined)lazyLoadComparison();
-for(constkeyofkeys){
-if(typeofactual[key]==='string'&&
-isRegExp(expected[key])&&
-expected[key].test(actual[key])){
-continue;
+}else{
+// Handle validation objects.
+constkeys=ObjectKeys(expected);
+// Special handle errors to make sure the name and the message are
+// compared as well.
+if(expectedinstanceofError){
+keys.push('name','message');
+}elseif(keys.length===0){
+thrownewERR_INVALID_ARG_VALUE('error',
+expected,'may not be an empty object');
+}
+if(isDeepEqual===undefined)lazyLoadComparison();
+for(constkeyofkeys){
+if(typeofactual[key]==='string'&&
+isRegExp(expected[key])&&
+expected[key].test(actual[key])){
+continue;
+}
+compareExceptionKey(actual,expected,key,message,keys,fn);
 }
-compareExceptionKey(actual,expected,key,message,keys,fn);
+return;
 }
-return;
-}
-
 // Guard instanceof against arrow functions as they don't have a prototype.
 // Check for matching Error classes.
-if(expected.prototype!==undefined&&actualinstanceofexpected){
+}elseif(expected.prototype!==undefined&&actualinstanceofexpected){
 return;
-}
-if(Error.isPrototypeOf(expected)){
+}elseif(ObjectPrototypeIsPrototypeOf(Error,expected)){
 throwactual;
+}else{
+// Check validation functions return value.
+constres=expected.call({},actual);
+if(res!==true){
+throwactual;
+}
 }
 
-// Check validation functions return value.
-constres=expected.call({},actual);
-if(res!==true){
-throwactual;
+if(throwError){
+consterr=newAssertionError({
+ actual,
+ expected,
+ message,
+operator: fn.name,
+stackStartFn: fn
+});
+err.generatedMessage=generatedMessage;
+throwerr;
 }
 }