Move hermesdebugger to OSS

Summary:
flybefree

Only moved, formatted the JSON and changed the headers.

changelog: New Hermes Debugger plugin for React Native apps.

Reviewed By: rickhanlonii

Differential Revision: D20673166

fbshipit-source-id: 9ecf4708f8834e00699d2d39aa6daa51c46a771b

desktop/plugins/hermesdebuggerrn/index.tsx

@@ -0,0 +1,135 @@
+/**
+ * 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.
+ *
+ * @format
+ */
+
+import React from 'react';
+import {FlipperDevicePlugin, Device} from 'flipper';
+import LaunchScreen from './LaunchScreen';
+import SelectScreen from './SelectScreen';
+import ErrorScreen from './ErrorScreen';
+import ChromeDevTools from './ChromeDevTools';
+
+const POLL_SECS = 5 * 1000;
+const METRO_HOST = 'http://localhost:8081';
+
+export type Target = Readonly<{
+  id: string;
+  description: string;
+  title: string;
+  faviconUrl: string;
+  devtoolsFrontendUrl: string;
+  type: string;
+  webSocketDebuggerUrl: string;
+  vm: string;
+}>;
+
+export type Targets = ReadonlyArray<Target>;
+
+type State = Readonly<{
+  targets?: Targets | null;
+  selectedTarget?: Target | null;
+  error?: Error | null;
+}>;
+
+export default class extends FlipperDevicePlugin<State, any, any> {
+  static title = 'Hermes Debugger';
+  static id = 'Hermesdebuggerrn';
+  static icon = 'code';
+
+  static supportsDevice(device: Device) {
+    return !device.isArchived && device.os === 'Metro';
+  }
+
+  state: State = {
+    targets: null,
+    selectedTarget: null,
+    error: null,
+  };
+
+  poll?: NodeJS.Timeout;
+
+  componentDidMount() {
+    // This is a pretty basic polling mechnaism. We ask Metro every POLL_SECS what the
+    // current available targets are and only handle a few basic state transitions.
+    this.poll = setInterval(this.checkDebugTargets, POLL_SECS);
+    this.checkDebugTargets();
+  }
+
+  componentWillUnmount() {
+    if (this.poll) {
+      clearInterval(this.poll);
+    }
+  }
+
+  checkDebugTargets = () => {
+    fetch(`${METRO_HOST}/json`)
+      .then((res) => res.json())
+      .then(
+        (result) => {
+          // We only want to use the Chrome Reload targets.
+          const targets = result.filter(
+            (target: any) =>
+              target.title ===
+              'React Native Experimental (Improved Chrome Reloads)',
+          );
+
+          // Find the currently selected target.
+          // If the current selectedTarget isn't returned, clear it.
+          let currentlySelected = null;
+          if (this.state.selectedTarget != null) {
+            for (const target of result) {
+              if (
+                this.state.selectedTarget?.webSocketDebuggerUrl ===
+                target.webSocketDebuggerUrl
+              ) {
+                currentlySelected = this.state.selectedTarget;
+              }
+            }
+          }
+
+          // Auto-select the first target if there is one,
+          // but don't change the one that's already selected.
+          const selectedTarget =
+            currentlySelected == null && targets.length === 1
+              ? targets[0]
+              : currentlySelected;
+
+          this.setState({
+            error: null,
+            targets,
+            selectedTarget,
+          });
+        },
+        (error) => {
+          this.setState({
+            targets: null,
+            selectedTarget: null,
+            error,
+          });
+        },
+      );
+  };
+
+  handleSelect = (selectedTarget: Target) => this.setState({selectedTarget});
+
+  render() {
+    const {error, selectedTarget, targets} = this.state;
+
+    if (selectedTarget) {
+      return <ChromeDevTools url={selectedTarget.devtoolsFrontendUrl} />;
+    } else if (targets != null && targets.length === 0) {
+      return <LaunchScreen />;
+    } else if (targets != null && targets.length > 0) {
+      return <SelectScreen targets={targets} onSelect={this.handleSelect} />;
+    } else if (error != null) {
+      return <ErrorScreen error={error} />;
+    } else {
+      return null;
+    }
+  }
+}