将具有决心和拒绝的承诺转换为异步功能(木偶师)的正确方法

Question

所以我对异步函数和承诺很陌生，想象一个这样的承诺(请求忽略语法错误(

await new Promise(async (resolve, reject ) => {
const page = await browser.newPage();
await page.goto('https://example.com').catch( ()=>reject('ERROR -> LINK 1 TIMEOUT '));
// INSERT USERNAME AND PASSWORD 
await page.$eval('form', form => form.submit()).catch( ()=>reject('ERROR -> FORM SUBMIT ERROR '));
if( await page.$("#username"))
{
reject(" ERROR -> LOGIN FAILED !!!!!!!!!!!!!! ");
}


await page.waitForSelector('#xxx').catch( ()=>reject('ERROR -> WAITING FOR ELEMENT TIMEOUT '));
var scraped_data = // dop some page evaluate and scrap data;
resolve(scraped_data);
}).then(function(scraped_data){
await page.close();
console.log('all done');
insert_data_in_databas(scraped_data);
})
.catch(function(error){
console.log(' tab failed : ');
console.log(error);
});

我想将其转换为异步函数...正确的方法是什么？我应该把它们都放在一个尝试/捕获块中吗

async function do_stuff(){
try {
const page    = await browser.newPage();
await page.setViewport({ width: 1000, height: 1100});
await page.goto( 'https://example.com'  );
// INSERT USERNAME AND PASSWORD 
await page.$eval('form', form => form.submit());
await page.waitForSelector('#xxx');
var scraped_data = // dop some page evaluate and scrap data;
await page.close();
console.log('all done');
insert_data_in_databas(scraped_data);    
}
catch (e) {
await page.close();
console.log('error');
console.log(e);
}
}

当出现错误时如何拒绝，以便其余代码无法执行？ 我可以在 catche 块中包含自定义错误文本吗，例如

ERROR -> FORM SUBMIT ERROR 

我应该怎么做

if( await page.$("#username"))
{
reject(" ERROR -> LOGIN FAILED !!!!!!!!!!!!!! ");
}

这不是try/catche中的实际错误(我的意思是它不是代码错误(？

------------------------------------------编辑--------------------

我试过了

async function open_tab(){
try {
const page    = await browser.newPage();
await page.setViewport({ width: 1000, height: 1100});
await page.goto( 'https://google.com'  );
await page.waitForSelector('#xxx').catch(()=> { throw new Error('ERROR -> LOGIN FAILED')});
await page.close();
console.log('all done');
}
catch (e) {
console.log('error');
console.log(e);
await page.close();
}
}

它几乎可以工作，但我无法关闭我得到的捕获块中的选项卡

UnhandledPromiseRejectionWarning: ReferenceError: page is not defined

并且选项卡保持打开状态，这并不理想

Answer 1

不应该有new Promise，因为承诺已经存在并且可以链接。

如果结果承诺应该在函数中被拒绝async则为：

if (await page.$("#username")) {
throw new Error('ERROR -> LOGIN FAILED');
}

它应该是

let page;
try {
page    = await browser.newPage();

而不是

try {
const page    = await browser.newPage();

Answer 2

//木偶师错误处理的最佳解决方案

const puppeteer = require("puppeteer");
const param_puppeteer = {
args: [
"--incognito",
"--ignore-certificate-errors",
"--no-sandbox",
"--disable-setuid-sandbox",
"--window-size=1920,1080",
"--disable-accelerated-2d-canvas",
"--disable-gpu",
// '--unlimited-storage',
// '--no-startup-window',
// '--disable-dev-shm-usage',
// '--disable-crash-reporter',
// '--disable-breakpad'
],
headless: false,
};
async function start() {
return puppeteer
.launch(param_puppeteer)
.then(async (browser) => {
const page = await browser.newPage();
return await task(page)
.catch((err) => console.log(err))
.finally(() => browser.close());
})
.catch((err) => console.log(err));
}
async function task(page) {
await page.setViewport({ width: 1000, height: 1100 });
await page.goto("https://google.com");
await page.waitForSelector("#hplogo");
let exist = await page.$("#hplogo").then((res) => !!res);
if (exist) {
return new Promise((resolve, reject) => resolve("success"));
} else {
return new Promise((resolve, reject) => reject("failed"));
}
}
start();