您好,感谢编写这份教程,对正在从 JavaScript 转向 Python 的开发者帮助很大。
在阅读《Pythonic Code》章节关于 with 语句的部分时,我注意到文中提到:
JavaScript 没有对应的语法。
我认为这个描述可能需要补充说明。
虽然早期 JavaScript 确实没有类似语法,但随着 Explicit Resource Management 提案进入标准,JavaScript 已经提供了 using 和 await using 语句用于资源管理,例如:
using file = openFile();
// 使用 file
离开作用域后会自动调用:
fileSymbol.dispose
异步资源则会调用:
await fileSymbol.asyncDispose
从使用场景来看,它与 Python 的:
with open("file.txt") as file:
...
都用于确保资源在使用结束后被自动释放,因此对于学习者来说,using 可以视为 JavaScript 中最接近 with 的对应概念。
当然两者底层机制并不完全相同:
Python 基于 enter / exit
JavaScript 基于 Symbol.dispose / Symbol.asyncDispose
因此或许可以考虑将原文调整为类似:
JavaScript 早期没有对应语法,但现代 JavaScript 已提供 using 语句作为资源管理方案,其设计目标与 Python 的 with 语句较为接近。
这样对于从 JavaScript 转向 Python 的读者来说,理解两种语言的资源管理方式可能会更容易一些。
感谢分享这份优秀的教程!
Hi, thanks for the excellent tutorial!
While reading the section about Python's with statement, I noticed the following statement:
JavaScript does not have an equivalent syntax.
This was historically true, but since the introduction of the Explicit Resource Management proposal, JavaScript now includes the using and await using statements.
Example:
using file = openFile();
// use file
When execution leaves the scope, JavaScript automatically invokes:
fileSymbol.dispose
or
await fileSymbol.asyncDispose
This provides automatic resource cleanup and is conceptually quite similar to Python's:
with open("file.txt") as file:
...
Of course, the mechanisms are different:
Python uses the context manager protocol (enter / exit)
JavaScript uses Symbol.dispose / Symbol.asyncDispose
But from a learner's perspective, using is probably the closest JavaScript equivalent to with.
It may be worth updating the text to clarify that modern JavaScript now has a comparable resource-management syntax.
References:
MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/using
TC39 Explicit Resource Management Proposal: https://github.com/tc39/proposal-explicit-resource-management
Thanks again for the great content!
您好,感谢编写这份教程,对正在从 JavaScript 转向 Python 的开发者帮助很大。
在阅读《Pythonic Code》章节关于 with 语句的部分时,我注意到文中提到:
JavaScript 没有对应的语法。
我认为这个描述可能需要补充说明。
虽然早期 JavaScript 确实没有类似语法,但随着 Explicit Resource Management 提案进入标准,JavaScript 已经提供了 using 和 await using 语句用于资源管理,例如:
using file = openFile();
// 使用 file
离开作用域后会自动调用:
fileSymbol.dispose
异步资源则会调用:
await fileSymbol.asyncDispose
从使用场景来看,它与 Python 的:
with open("file.txt") as file:
...
都用于确保资源在使用结束后被自动释放,因此对于学习者来说,using 可以视为 JavaScript 中最接近 with 的对应概念。
当然两者底层机制并不完全相同:
Python 基于 enter / exit
JavaScript 基于 Symbol.dispose / Symbol.asyncDispose
因此或许可以考虑将原文调整为类似:
JavaScript 早期没有对应语法,但现代 JavaScript 已提供 using 语句作为资源管理方案,其设计目标与 Python 的 with 语句较为接近。
这样对于从 JavaScript 转向 Python 的读者来说,理解两种语言的资源管理方式可能会更容易一些。
感谢分享这份优秀的教程!
Hi, thanks for the excellent tutorial!
While reading the section about Python's with statement, I noticed the following statement:
JavaScript does not have an equivalent syntax.
This was historically true, but since the introduction of the Explicit Resource Management proposal, JavaScript now includes the using and await using statements.
Example:
using file = openFile();
// use file
When execution leaves the scope, JavaScript automatically invokes:
fileSymbol.dispose
or
await fileSymbol.asyncDispose
This provides automatic resource cleanup and is conceptually quite similar to Python's:
with open("file.txt") as file:
...
Of course, the mechanisms are different:
Python uses the context manager protocol (enter / exit)
JavaScript uses Symbol.dispose / Symbol.asyncDispose
But from a learner's perspective, using is probably the closest JavaScript equivalent to with.
It may be worth updating the text to clarify that modern JavaScript now has a comparable resource-management syntax.
References:
MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/using
TC39 Explicit Resource Management Proposal: https://github.com/tc39/proposal-explicit-resource-management
Thanks again for the great content!