安全赋值运算符 () 提案符旨在简化代码中的错误处理,使代码更易于阅读,特别是在处理可能失败或抛出错误的函数时。当使用运算符时,它会检查函数或操作是否成功。如果成功,它会返回结果。如果失败,它会返回错误信息而不会让程序崩溃。 直接上代码对比: Before: asyncfunctiongetData(){try{constres=awaitfetch('https:...
=` 运算符 安全赋值运算符 (?=) 提案符旨在简化代码中的错误处理,使代码更易于阅读,特别是在处理可能失败或抛出错误的函数时。 当使用?=运算符时,它会检查函数或操作是否成功。如果成功,它会返回结果。如果失败,它会返回错误信息而不会让程序崩溃。 直接上代码对比: Before: 复制代码 1 2 3 4 5 6 7 8 ...
In this chapter we continue our consideration of lexical environments. In the previoussub chapter 3.1we clarified the general theory related with the topic. In particular we have learned that the concept of environments is closely related with concepts ofstatic scopeandclosures.Continue reading→ ...
Chapter 6: Symbols and Symbol Properties introduces the concept of symbols, a new way to define properties. Symbols are a new primitive type that can be used to obscure (but not hide) object properties and methods. Chapter 7: Sets and Maps details the new collection types of Set, WeakSet,...
The concept is rolled out at a European level, the tools are available to all award winners and finalists to support their own marketing. Later in 2013, the award-winning packaging and the finalists will be touring throughout Europe and in 2014 they will be presented at Interpack. I would ...
At the end of July 2014, TC39 [^1] had another meeting, during which the last details of the ECMAScript 6 (ES6) module syntax were finalized. This blog post gives an overview of the complete ES6 module system.
data:URLs only resolveBare specifiersfor builtin modules andAbsolute specifiers. ResolvingRelative specifiersdoes not work becausedata:is not aspecial scheme. For example, attempting to load./foofromdata:text/javascript,import "./foo";fails to resolve because there is no concept of relative resolutio...
历时将近6年的时间来制定的新 ECMAScript 标准 ECMAScript 6(亦称 ECMAScript Harmony,简称 ES6)终于在 2015 年 6 月正式发布。自从上一个标准版本 ES5 在 2009 年发布以后,ES6 就一直以新语法、新特性的优越性吸引著众多JavaScript开发者,驱使他们积极尝鲜。
The tuple-it npm package, which introduces a similar concept but modifies the Promise and Function prototypes—an approach that is less ideal.tuple-it npm 包,引入了类似的概念但修改了 Promise 和Function 原型——这种方法不太理想。 The frequent oversight of error handling in JavaScript code. JavaScr...
The most important state-related concept remains “settledness”: a promise is settled if it is either fulfilled or rejected. After a promise is settled, it doesn’t change, anymore (state and fulfillment or rejection value). If you want to implement promises then “resolving” matters, too ...