Web Front-end
JS Tutorial
Will await wait when Promise is not resolved or rejected in JavaScript?
Will await wait when Promise is not resolved or rejected in JavaScript?
JavaScript asynchronous programming: pending states of async/await and promises
async/await is an elegant way to handle asynchronous operations in JavaScript, but its behavior is worth exploring in depth when the Promise is in a long-term pending state. This article will analyze the performance of await when the Promise is not resolve or reject .
Scenario Analysis
Consider the following code:
async function yyy() {
console.log('yyy calls xxx to start');
let res = await xxx();
console.log('yyy call xxx ends', res);
}
async function xxx() {
return new Promise(function(resolve, reject) {
// No resolve or reject call});
}
yyy(); The xxx function returns a promise that is always in the pending state. What happens with await xxx() in the yyy function?
Environment Differences: Node.js vs. Browser
The behavior of await is affected by the operating environment:
Node.js: If Promise remains pending and there are no other active asynchronous operations (such as timers, network requests), the Node.js event loop will consider the program to be completed and exited. It won't wait for the pending Promise indefinitely.
Browser: In a browser environment, await will usually wait for the Promise to complete. However, if other asynchronous tasks are lacking to drive the event loop, the browser engine may think that the script has been executed and will not block page rendering or interaction. But if the script is executed synchronously (for example, directly
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
Download the official website of Ouyi Exchange app for Apple mobile phone
Apr 28, 2025 pm 06:57 PM
The Ouyi Exchange app supports downloading of Apple mobile phones, visit the official website, click the "Apple Mobile" option, obtain and install it in the App Store, register or log in to conduct cryptocurrency trading.
Which of the top ten currency trading platforms in the world are the latest version of the top ten currency trading platforms
Apr 28, 2025 pm 08:09 PM
The top ten cryptocurrency trading platforms in the world include Binance, OKX, Gate.io, Coinbase, Kraken, Huobi Global, Bitfinex, Bittrex, KuCoin and Poloniex, all of which provide a variety of trading methods and powerful security measures.
What are the top currency trading platforms? The top 10 latest virtual currency exchanges
Apr 28, 2025 pm 08:06 PM
Currently ranked among the top ten virtual currency exchanges: 1. Binance, 2. OKX, 3. Gate.io, 4. Coin library, 5. Siren, 6. Huobi Global Station, 7. Bybit, 8. Kucoin, 9. Bitcoin, 10. bit stamp.
What are the top ten virtual currency trading apps? The latest digital currency exchange rankings
Apr 28, 2025 pm 08:03 PM
The top ten digital currency exchanges such as Binance, OKX, gate.io have improved their systems, efficient diversified transactions and strict security measures.
Which of the top ten currency trading platforms in the world are among the top ten currency trading platforms in 2025
Apr 28, 2025 pm 08:12 PM
The top ten cryptocurrency exchanges in the world in 2025 include Binance, OKX, Gate.io, Coinbase, Kraken, Huobi, Bitfinex, KuCoin, Bittrex and Poloniex, all of which are known for their high trading volume and security.
How to measure thread performance in C?
Apr 28, 2025 pm 10:21 PM
Measuring thread performance in C can use the timing tools, performance analysis tools, and custom timers in the standard library. 1. Use the library to measure execution time. 2. Use gprof for performance analysis. The steps include adding the -pg option during compilation, running the program to generate a gmon.out file, and generating a performance report. 3. Use Valgrind's Callgrind module to perform more detailed analysis. The steps include running the program to generate the callgrind.out file and viewing the results using kcachegrind. 4. Custom timers can flexibly measure the execution time of a specific code segment. These methods help to fully understand thread performance and optimize code.
How much is Bitcoin worth
Apr 28, 2025 pm 07:42 PM
Bitcoin’s price ranges from $20,000 to $30,000. 1. Bitcoin’s price has fluctuated dramatically since 2009, reaching nearly $20,000 in 2017 and nearly $60,000 in 2021. 2. Prices are affected by factors such as market demand, supply, and macroeconomic environment. 3. Get real-time prices through exchanges, mobile apps and websites. 4. Bitcoin price is highly volatile, driven by market sentiment and external factors. 5. It has a certain relationship with traditional financial markets and is affected by global stock markets, the strength of the US dollar, etc. 6. The long-term trend is bullish, but risks need to be assessed with caution.
Binance official website entrance Binance official latest entrance 2025
Apr 28, 2025 pm 07:54 PM
Visit Binance official website and check HTTPS and green lock logos to avoid phishing websites, and official applications can also be accessed safely.
