如何在Electron中运行映射后的函数

Question

我正在加密一个文件数组，并使用节点流加密区块中的文件。我想在对数组中的所有文件进行加密后运行函数，但我的函数在加密完成之前运行。我正在使用preload.js来公开加密函数。

//encrypt.js
const path = require("path");
const fs = require("fs");
const { pipeline } = require("stream/promises");
const { app } = require("./app.js");
async function encrypt(file) {
const fileReadStream = fs.createReadStream(file);
const filePath = path.parse(file).dir;
const fileName = path.parse(file).name;
const fileExt = path.parse(file).ext;
const EncFile = filePath + "/" + fileName + "_enc" + fileExt;
const fileWriteStream = fs.createWriteStream(EncFile);
await pipeline(
fileReadStream,
new Transform({
transform(chunk, encoding, callback) {
const encryptedData = app.encrypt(chunk, password);
callback(null, encryptedData);
console.log("File encrypted");
},
}),
fileWriteStream
);
}
module.exports.encrypt = encrypt;

//preload.js
const { encrypt } = require('./encrypt.js');
contextBridge.exposeInMainWorld('encrypt', encrypt);

const para = document.querySelector('#para-info');
const btn = document.querySelector('#btn');
btn.addEventListener("click", () => {
filesList.map(file => {
window.encrypt(file, password);
});
done();
}
// function i want to run after encryption is done
function done(){
para.innerText = 'Encryption Done';
}

Answer 1

函数为async:

async function encrypt(file) {

但它并没有被等待：

filesList.map(file => {
window.encrypt(file, password);
});
done();

一种方法是在async函数中使用await:来完成所有这些操作

let myFunc = async () => {
for (let file of filesList) {
await window.encrypt(file, password);
}
done();
};
myFunc();

或者捕获生成的Promise对象并等待所有对象：

let promises = filesList.map(file => {
return window.encrypt(file, password);
});
Promise.all(promises).then(() => done());

Answer 2

您可以让您点击处理程序作为异步函数

const para = document.querySelector('#para-info');
const btn = document.querySelector('#btn');
btn.addEventListener("click", async () => {
const promises = filesList.map(file => window.encrypt(file, password);
// Waits for every promise in list
await Promise.all(promises);
done();
}
// function i want to run after encryption is done
function done(){
para.innerText = 'Encryption Done';
}