Remove Error: prefix

These don't really make sense to add to the message string since these prefixes
are typically printed when the errors are printed anyway and are part of .stack.

So prefixing just leads to duplicate prefixes.

Author: sebmarkbage

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -799,12 +799,12 @@ describe('ReactFlight', () => {
             <Throw value={new TypeError('This is a real Error.')} />
           </div>
         </ClientErrorBoundary>
-        <ClientErrorBoundary expectedMessage="Error: This is a string error.">
+        <ClientErrorBoundary expectedMessage="This is a string error.">
           <div>
             <Throw value="This is a string error." />
           </div>
         </ClientErrorBoundary>
-        <ClientErrorBoundary expectedMessage="Error: {message: ..., extra: ..., nested: ...}">
+        <ClientErrorBoundary expectedMessage="{message: ..., extra: ..., nested: ...}">
           <div>
             <Throw
               value={{
@@ -816,9 +816,7 @@ describe('ReactFlight', () => {
           </div>
         </ClientErrorBoundary>
         <ClientErrorBoundary
-          expectedMessage={
-            'Error: {message: "Short", extra: ..., nested: ...}'
-          }>
+          expectedMessage={'{message: "Short", extra: ..., nested: ...}'}>
           <div>
             <Throw
               value={{
@@ -829,32 +827,32 @@ describe('ReactFlight', () => {
             />
           </div>
         </ClientErrorBoundary>
-        <ClientErrorBoundary expectedMessage="Error: Symbol(hello)">
+        <ClientErrorBoundary expectedMessage="Symbol(hello)">
           <div>
             <Throw value={Symbol('hello')} />
           </div>
         </ClientErrorBoundary>
-        <ClientErrorBoundary expectedMessage="Error: 123">
+        <ClientErrorBoundary expectedMessage="123">
           <div>
             <Throw value={123} />
           </div>
         </ClientErrorBoundary>
-        <ClientErrorBoundary expectedMessage="Error: undefined">
+        <ClientErrorBoundary expectedMessage="undefined">
           <div>
             <Throw value={undefined} />
           </div>
         </ClientErrorBoundary>
-        <ClientErrorBoundary expectedMessage="Error: <div/>">
+        <ClientErrorBoundary expectedMessage="<div/>">
           <div>
             <Throw value={<div />} />
           </div>
         </ClientErrorBoundary>
-        <ClientErrorBoundary expectedMessage="Error: function Foo() {}">
+        <ClientErrorBoundary expectedMessage="function Foo() {}">
           <div>
             <Throw value={function Foo() {}} />
           </div>
         </ClientErrorBoundary>
-        <ClientErrorBoundary expectedMessage={'Error: ["array"]'}>
+        <ClientErrorBoundary expectedMessage={'["array"]'}>
           <div>
             <Throw value={['array']} />
           </div>

packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js

@@ -919,9 +919,7 @@ describe('ReactFlightDOM', () => {
       abort('for reasons');
     });
     if (__DEV__) {
-      expect(container.innerHTML).toBe(
-        '<p>Error: for reasons + a dev digest</p>',
-      );
+      expect(container.innerHTML).toBe('<p>for reasons + a dev digest</p>');
     } else {
       expect(container.innerHTML).toBe('<p>digest("for reasons")</p>');
     }

packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js

@@ -583,7 +583,7 @@ describe('ReactFlightDOMBrowser', () => {
       controller.abort('for reasons');
     });
     const expectedValue = __DEV__
-      ? '<p>Error: for reasons + a dev digest</p>'
+      ? '<p>for reasons + a dev digest</p>'
       : '<p>digest("for reasons")</p>';
     expect(container.innerHTML).toBe(expectedValue);
 

packages/react-server/src/ReactFizzServer.js

@@ -823,10 +823,10 @@ function encodeErrorForBoundary(
       // eslint-disable-next-line react-internal/safe-string-coercion
       message = String(error.message);
     } else if (typeof error === 'object' && error !== null) {
-      message = 'Error: ' + describeObjectForErrorMessage(error);
+      message = describeObjectForErrorMessage(error);
     } else {
       // eslint-disable-next-line react-internal/safe-string-coercion
-      message = 'Error: ' + String(error);
+      message = String(error);
     }
 
     boundary.errorMessage = message;

packages/react-server/src/ReactFlightServer.js

@@ -1678,10 +1678,10 @@ function emitErrorChunk(
         // eslint-disable-next-line react-internal/safe-string-coercion
         stack = String(error.stack);
       } else if (typeof error === 'object' && error !== null) {
-        message = 'Error: ' + describeObjectForErrorMessage(error);
+        message = describeObjectForErrorMessage(error);
       } else {
         // eslint-disable-next-line react-internal/safe-string-coercion
-        message = 'Error: ' + String(error);
+        message = String(error);
       }
     } catch (x) {
       message = 'An error occurred but serializing the error message failed.';