assert: do not repeat .throws() code

This refactors some code for less duplication.
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

@@ -563,6 +563,7 @@ function compareExceptionKey(actual, expected, key, message, keys, fn) {
 
 functionexpectedException(actual,expected,message,fn){
 letgeneratedMessage=false;
+letthrowError=false;
 
 if(typeofexpected!=='function'){
 // Handle regular expressions.
@@ -576,20 +577,9 @@ 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,
@@ -599,36 +589,33 @@ function expectedException(actual, expected, message, fn) {
 });
 err.operator=fn.name;
 throwerr;
-}
-
-// Handle validation objects.
-constkeys=Object.keys(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=Object.keys(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');
 }
-compareExceptionKey(actual,expected,key,message,keys,fn);
+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);
+}
+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(ObjectPrototype.isPrototypeOf(Error,expected)){
+}elseif(ObjectPrototype.isPrototypeOf(Error,expected)){
 if(!message){
 generatedMessage=true;
 message='The error is expected to be an instance of '+
@@ -639,26 +626,22 @@ function expectedException(actual, expected, message, fn) {
 message+=`"${inspect(actual,{depth: -1})}"`;
 }
 }
-consterr=newAssertionError({
- actual,
- expected,
- message,
-operator: fn.name,
-stackStartFn: fn
-});
-err.generatedMessage=generatedMessage;
-throwerr;
+throwError=true;
+}else{
+// Check validation functions return value.
+constres=expected.call({},actual);
+if(res!==true){
+if(!message){
+generatedMessage=true;
+constname=expected.name ? `"${expected.name}" ` : '';
+message=`The ${name}validation function is expected to return`+
+` "true". Received ${inspect(res)}`;
+}
+throwError=true;
+}
 }
 
-// Check validation functions return value.
-constres=expected.call({},actual);
-if(res!==true){
-if(!message){
-generatedMessage=true;
-constname=expected.name ? `"${expected.name}" ` : '';
-message=`The ${name}validation function is expected to return "true".`+
-` Received ${inspect(res)}`;
-}
+if(throwError){
 consterr=newAssertionError({
  actual,
  expected,