Files
react/packages/react-devtools-extensions/src/injectGlobalHook.js

94 lines
3.6 KiB
JavaScript

/* global chrome */
import nullthrows from 'nullthrows';
import {installHook} from 'react-devtools-shared/src/hook';
import {SESSION_STORAGE_RELOAD_AND_PROFILE_KEY} from 'react-devtools-shared/src/constants';
import {sessionStorageGetItem} from 'react-devtools-shared/src/storage';
function injectCode(code) {
const script = document.createElement('script');
script.textContent = code;
// This script runs before the <head> element is created,
// so we add the script to <html> instead.
nullthrows(document.documentElement).appendChild(script);
nullthrows(script.parentNode).removeChild(script);
}
let lastDetectionResult;
// We want to detect when a renderer attaches, and notify the "background page"
// (which is shared between tabs and can highlight the React icon).
// Currently we are in "content script" context, so we can't listen to the hook directly
// (it will be injected directly into the page).
// So instead, the hook will use postMessage() to pass message to us here.
// And when this happens, we'll send a message to the "background page".
window.addEventListener('message', function(evt) {
if (evt.source !== window || !evt.data) {
return;
}
if (evt.data.source === 'react-devtools-detector') {
lastDetectionResult = {
hasDetectedReact: true,
reactBuildType: evt.data.reactBuildType,
};
chrome.runtime.sendMessage(lastDetectionResult);
} else if (evt.data.source === 'react-devtools-inject-backend') {
const script = document.createElement('script');
script.src = chrome.runtime.getURL('build/backend.js');
document.documentElement.appendChild(script);
script.parentNode.removeChild(script);
}
});
// NOTE: Firefox WebExtensions content scripts are still alive and not re-injected
// while navigating the history to a document that has not been destroyed yet,
// replay the last detection result if the content script is active and the
// document has been hidden and shown again.
window.addEventListener('pageshow', function(evt) {
if (!lastDetectionResult || evt.target !== window.document) {
return;
}
chrome.runtime.sendMessage(lastDetectionResult);
});
const detectReact = `
window.__REACT_DEVTOOLS_GLOBAL_HOOK__.on('renderer', function(evt) {
window.postMessage({
source: 'react-devtools-detector',
reactBuildType: evt.reactBuildType,
}, '*');
});
`;
const saveNativeValues = `
window.__REACT_DEVTOOLS_GLOBAL_HOOK__.nativeObjectCreate = Object.create;
window.__REACT_DEVTOOLS_GLOBAL_HOOK__.nativeMap = Map;
window.__REACT_DEVTOOLS_GLOBAL_HOOK__.nativeWeakMap = WeakMap;
window.__REACT_DEVTOOLS_GLOBAL_HOOK__.nativeSet = Set;
`;
// If we have just reloaded to profile, we need to inject the renderer interface before the app loads.
if (sessionStorageGetItem(SESSION_STORAGE_RELOAD_AND_PROFILE_KEY) === 'true') {
const rendererURL = chrome.runtime.getURL('build/renderer.js');
let rendererCode;
// We need to inject in time to catch the initial mount.
// This means we need to synchronously read the renderer code itself,
// and synchronously inject it into the page.
// There are very few ways to actually do this.
// This seems to be the best approach.
const request = new XMLHttpRequest();
request.addEventListener('load', function() {
rendererCode = this.responseText;
});
request.open('GET', rendererURL, false);
request.send();
injectCode(rendererCode);
}
// Inject a `__REACT_DEVTOOLS_GLOBAL_HOOK__` global so that React can detect that the
// devtools are installed (and skip its suggestion to install the devtools).
injectCode(
';(' + installHook.toString() + '(window))' + saveNativeValues + detectReact,
);