将参数从脚本传递到gulp任务 [英] Pass argument from script to gulp task

问题描述

我有package.json脚本，其结构如下:

I have package.json scripts with the following structure:

"scripts": {
    "watch:build": "tsc --watch",
    "watch:server": "nodemon ./src/app.js --watch 'app'",
    "build": "tsc && gulp do_something",
    "start": "npm-run-all clean build --parallel watch:build", 
    "watch:server --print-label"
}

我想以npm run start with_argument的身份启动该应用程序 并将其传递给build脚本，以根据该参数在gulp任务中执行操作.

I would like to start the application as npm run start with_argument and pass it to build script, to perform actions in the gulp task based on that argument.

我阅读了很多教程以及如何撰写文章，但没有结果.可能会以某种方式将参数从一个脚本传递到另一个脚本(这会启动一项gulp任务).

I read a lot of tutorial and how to articles, but without result. It is possible somehow to pass argument from one script to another(which starts a gulp task).

提前谢谢！

推荐答案

npm-run-all提供了自己的自定义机制，可以通过使用npm-scripts中的占位符来处理自变量，如 Argument Placeholders 中所述.在其文档部分找到这里.

npm-run-all provides a its own custom mechanism for handling arguments by utilizing placeholders in npm-scripts, as stated in the Argument Placeholders section of its documentation found here.

鉴于您当前的名为start的npm脚本，您需要按以下方式重新定义它:

Given your current npm-script named start you'll need to redefine it as follows:

"scripts": {
  ...
  "start": "npm-run-all clean \"build -- {@}\" --parallel watch:build --"
  ...
}

注释:

• -- {@}必须在build之后添加. ¹
• build -- {@}必须用转义的双引号引起来\"...\"
在最后一次脚本调用之后还必须添加
• --，即:watch:build

• -- {@} must be added after build.¹
• build -- {@} must be wrapped in escaped double quotes \"...\"
• -- must also be added after last script invocation, namely: watch:build

要获取在 gulpfile.js 中通过CLI传递的参数，您将需要使用节点

To obtain the arguments passed via the CLI inside your gulpfile.js you''ll need to utilize nodes process.argv

为了演示起见，我们的 gulpfile.js 如下:

For the purpose of demonstration lets say our gulpfile.js is as follows:

var gulp = require('gulp');
var args = process.argv.splice(3, process.argv.length - 3);

gulp.task('doSomething', function() {

  // For testing purposes...
  if (args.indexOf('--foo') > -1) {
    console.log('--foo was passed via the CLI.')
  }

  if (args.indexOf('--quux') > -1) {
    console.log('--quux was passed via the CLI.')
  }
});

注释:

1. 节点process.argv中的前三项是:

• 运行JavaScript文件的可执行文件的路径.
• 正在执行的JavaScript文件的路径.
• gulp任务的名称，即doSomething

但是，我们只对数组中第四项以后的元素感兴趣-因为这些将是通过CLI传递的参数.该行显示为:

However, we're only interested in the elements from the fourth item in the array onwards - as these will be the arguments passed via the CLI. The line which reads:

var args = process.argv.splice(3, process.argv.length - 3);

创建一个args变量并分配一个包含通过CLI传递的每个参数的数组，即，我们使用数组

creates an args variable and assigns an Array containing each argument passed via the CLI, i.e. we omit the first three aforementioned items in point 1 above using the Arrays splice() method.

---

运行您的start脚本:

您可以通过CLI调用启动脚本，如下所示:

---

Running your start script:

You invoke your start script via your CLI as follows:

$ npm start -- --foo --quux

注意:在提供自己的参数之前，您必须提供--在npm start之前.

Note You must provide the -- which precedes npm start before providing your own arguments.

• 使用上述人为设计的gulpfile.js，结合您在 package.json 中定义的当前脚本，当然还要对start脚本进行必要的更改.运行时:

• Using the contrived gulpfile.js above, in combination with your current scripts defined in your package.json, and of course the necessary changes made to your start script. When you run:

$ npm start -- --foo --quux

您将看到以下内容打印到控制台:

you will see the following printed to the console:

--foo was passed via the CLI.

--quux was passed via the CLI.

运行:

Running:

$ npm start -- --quux

您将只看到以下内容打印到控制台:

you will see just the following printed to the console:

--quux was passed via the CLI.

当然，正在运行:

And of course, running:

$ npm start

不打印 gulpfile.js 中定义的任何一条消息.

Does not print either of the messages defined in gulpfile.js.

_脚注:

_Footnotes:

1 _{-- {@}.但是，-- {@}处理多个参数，因此也可以将其用于一个参数.}

1 _{-- {@} can be replaced with -- {1} if you only intend to pass one argument. However, -- {@} handles multiple arguments, so it's fine to use it for one argument too.}

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