React.warn() and React.error()

packages/react/src/React.js

@@ -45,6 +45,7 @@ import {
   cloneElementWithValidation,
 } from './ReactElementValidator';
 import ReactSharedInternals from './ReactSharedInternals';
+import {error, warn} from './withComponentStack';
 import {enableStableConcurrentModeAPIs} from 'shared/ReactFeatureFlags';
 
 const React = {
@@ -65,6 +66,9 @@ const React = {
   lazy,
   memo,
 
+  error,
+  warn,
+
   useCallback,
   useContext,
   useEffect,

packages/react/src/__tests__/withComponentStack-test.js

@@ -0,0 +1,192 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+function normalizeCodeLocInfo(str) {
+  return str && str.replace(/at .+?:\d+/g, 'at **');
+}
+
+function expectHelper(spy, prefix, ...expectedArgs) {
+  const expectedStack = expectedArgs.pop();
+
+  expect(spy).toHaveBeenCalledTimes(1);
+
+  const actualArgs = spy.calls.mostRecent().args;
+
+  let actualStack = undefined;
+  if (expectedStack !== undefined) {
+    actualStack = actualArgs.pop();
+    expect(normalizeCodeLocInfo(actualStack)).toBe(expectedStack);
+  }
+
+  expect(actualArgs).toHaveLength(expectedArgs.length);
+  actualArgs.forEach((actualArg, index) => {
+    const expectedArg = expectedArgs[index];
+    expect(actualArg).toBe(
+      index === 0 ? `${prefix}: ${expectedArg}` : expectedArg,
+    );
+  });
+}
+
+function expectMessageAndStack(...expectedArgs) {
+  expectHelper(console.error, 'error', ...expectedArgs);
+  expectHelper(console.warn, 'warn', ...expectedArgs);
+}
+
+describe('withComponentStack', () => {
+  let React = null;
+  let ReactTestRenderer = null;
+  let error = null;
+  let scheduler = null;
+  let warn = null;
+
+  beforeEach(() => {
+    jest.resetModules();
+    jest.mock('scheduler', () => require('scheduler/unstable_mock'));
+
+    React = require('react');
+    ReactTestRenderer = require('react-test-renderer');
+    scheduler = require('scheduler');
+
+    error = React.error;
+    warn = React.warn;
+
+    spyOnDevAndProd(console, 'error');
+    spyOnDevAndProd(console, 'warn');
+  });
+
+  if (!__DEV__) {
+    it('does nothing in production mode', () => {
+      error('error');
+      warn('warning');
+
+      expect(console.error).toHaveBeenCalledTimes(0);
+      expect(console.warn).toHaveBeenCalledTimes(0);
+    });
+  }
+
+  if (__DEV__) {
+    it('does not include component stack when called outside of render', () => {
+      error('error: logged outside of render');
+      warn('warn: logged outside of render');
+      expectMessageAndStack('logged outside of render', undefined);
+    });
+
+    it('should support multiple args', () => {
+      function Component() {
+        error('error: number:', 123, 'boolean:', true);
+        warn('warn: number:', 123, 'boolean:', true);
+        return null;
+      }
+
+      ReactTestRenderer.create(<Component />);
+
+      expectMessageAndStack(
+        'number:',
+        123,
+        'boolean:',
+        true,
+        '\n    in Component (at **)',
+      );
+    });
+
+    it('includes component stack when called from a render method', () => {
+      class Parent extends React.Component {
+        render() {
+          return <Child />;
+        }
+      }
+
+      function Child() {
+        error('error: logged in child render method');
+        warn('warn: logged in child render method');
+        return null;
+      }
+
+      ReactTestRenderer.create(<Parent />);
+
+      expectMessageAndStack(
+        'logged in child render method',
+        '\n    in Child (at **)' + '\n    in Parent (at **)',
+      );
+    });
+
+    it('includes component stack when called from a render phase lifecycle method', () => {
+      function Parent() {
+        return <Child />;
+      }
+
+      class Child extends React.Component {
+        UNSAFE_componentWillMount() {
+          error('error: logged in child cWM lifecycle');
+          warn('warn: logged in child cWM lifecycle');
+        }
+        render() {
+          return null;
+        }
+      }
+
+      ReactTestRenderer.create(<Parent />);
+
+      expectMessageAndStack(
+        'logged in child cWM lifecycle',
+        '\n    in Child (at **)' + '\n    in Parent (at **)',
+      );
+    });
+
+    it('includes component stack when called from a commit phase lifecycle method', () => {
+      function Parent() {
+        return <Child />;
+      }
+
+      class Child extends React.Component {
+        componentDidMount() {
+          error('error: logged in child cDM lifecycle');
+          warn('warn: logged in child cDM lifecycle');
+        }
+        render() {
+          return null;
+        }
+      }
+
+      ReactTestRenderer.create(<Parent />);
+
+      expectMessageAndStack(
+        'logged in child cDM lifecycle',
+        '\n    in Child (at **)' + '\n    in Parent (at **)',
+      );
+    });
+
+    it('includes component stack when called from a passive effect handler', () => {
+      class Parent extends React.Component {
+        render() {
+          return <Child />;
+        }
+      }
+
+      function Child() {
+        React.useEffect(() => {
+          error('error: logged in child render method');
+          warn('warn: logged in child render method');
+        });
+        return null;
+      }
+
+      ReactTestRenderer.create(<Parent />);
+
+      scheduler.flushAll(); // Flush passive effects
+
+      expectMessageAndStack(
+        'logged in child render method',
+        '\n    in Child (at **)' + '\n    in Parent (at **)',
+      );
+    });
+  }
+});

packages/react/src/withComponentStack.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import ReactSharedInternals from 'shared/ReactSharedInternals';
+
+function noop() {}
+
+let error = noop;
+let warn = noop;
+if (__DEV__) {
+  const ReactDebugCurrentFrame = ReactSharedInternals.ReactDebugCurrentFrame;
+
+  error = (...args) => {
+    const stack = ReactDebugCurrentFrame.getStackAddendum();
+    if (stack !== '') {
+      console.error(...args, stack);
+    } else {
+      console.error(...args);
+    }
+  };
+
+  warn = (...args) => {
+    const stack = ReactDebugCurrentFrame.getStackAddendum();
+    if (stack !== '') {
+      console.warn(...args, stack);
+    } else {
+      console.warn(...args);
+    }
+  };
+}
+
+export {error, warn};