运行npm命令时会做什么? [英] What does -- do when running an npm command?

问题描述

例如，双破折号或两个连字符--的用法如下:

As an example, double dash or two hyphens -- is used like so:

npm test -- --coverage

在没有双破折号的情况下运行npm不会在覆盖模式下运行，因此似乎附加了后续标志，这是正确的吗?我找不到关于此的文档.

Running npm without the double dash flag does not run in coverage mode so it seems to append subsequent flags, is this correct? I couldn't find the documentation on this.

推荐答案

--本身作为参数已在所有UNIX命令中标准化:这意味着应将其他参数视为位置参数，而不是选项.请参阅 POSIX实用程序语法约定中的准则10.

-- as an argument on its own is standardized across all UNIX commands: It means that further arguments should be treated as positional arguments, not options. See Guideline 10 in POSIX Utility Syntax Conventions.

为了给您一个非基于NPM的示例，ls -- -l将查找名为-l的文件，因为--指定了所有后续参数都是位置性的.

To give you a non-NPM-based example, ls -- -l will look for a file named -l, because the -- specified that all subsequent arguments are positional.

在这种情况下，这意味着--coverage不是npm本身的参数；大概，然后，它随后由test子命令读取.对于遵循正确约定的工具，则没有必要，因为准则9指定所有选项都应在任何参数之前给出(因此，在这种情况下--coverage应被视为参数，因为它位于参数test之后)；但是，由于NPM仅部分遵循了指南，这是可以预见的结果.

In this context, it means that --coverage isn't an argument to npm itself; presumably, then, it's subsequently read by the test subcommand. For a tool that were following the conventions properly this wouldn't be necessary, because Guideline 9 specifies that all options shall be given before any arguments (thus that in this context --coverage should be treated as an argument since it comes after the argument test); however, inasmuch as NPM is only partially following the guidelines, this is a foreseeable result.

(长--option样式的选项实际上实际上是一个GNU扩展，所以我们这里是对多种解析样式的误解；不幸的是，这就是生活).

(Long --option-style options are actually a GNU extension as a whole, so what we have here is a mismash of multiple parsing styles; such is life, unfortunately).

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