preload.js

/**
 * The preload script runs before. It has access to web APIs
 * as well as Electron's renderer process modules and some
 * polyfilled Node.js functions.
 * 
 * https://www.electronjs.org/docs/latest/tutorial/sandbox
 */
window.addEventListener('DOMContentLoaded', () => {
	const replaceText = (selector, text) => {
		const element = document.getElementById(selector)
		if (element) element.innerText = text
	}

	for (const type of ['chrome', 'node', 'electron']) {
		replaceText(`${type}-version`, process.versions[type])
	}
})


// Preload (Isolated World)
// 三种方式在main与html之间通信
const {
	contextBridge,
	ipcRenderer
} = require('electron')
contextBridge.exposeInMainWorld(
	'ipcRenderer', {
		// From render to main.
		send: (channel, args) => {
			return ipcRenderer.sendSync(channel, 'ping')
		},
		// From main to render.
		// listener为自定义的消息处理函数，原型在renderer中
		receive: (channel, listener) => {
			ipcRenderer.on(channel, (event, args) => listener(args));
		},
		// From render to main and back again.
		invoke: (channel, args) => {
			return ipcRenderer.invoke(channel, args);
		}
	}

)