jswrap-brunch

Helps you wrap .js files with custom wrapper code before passing it through to the rest of the pipeline.

Installation

npm

npm install jswrap-brunch --save-dev

yarn

yarn add --dev jswrap-brunch

Usage

Configure by setting the jsWrap key in plugins in your brunch-config.js file. Its structure is as follows:

// brunch-config.js

{
  ...
  plugins: {
    ...
    jsWrap: {
      debug: [Boolean],
      wrappers: [
        {
          match: <Array[RegExp | String] | Regexp | String>,
          wrap: <Function(fileContents: String): String>,
          halt: [Boolean]
        },
      ]
    }
  }
}

wrappers is an array of objects defining match/wrap rules. Its attributes are:

• match: a string, a regexp, or an array of strings/regexps which will be used a filename tester. If any tester matches, the wrap proceeds.
• wrap: a function that takes the file contents and returns wrapped file contents.
• halt: a boolean indicating whether further matches shouldn't be considered after this one.

debug is a boolean value that will dump a bunch of matching information to the console if truthy to help you debug problems.

Motivation

I built this tool while trying to integrate the Stanford Javascript Crypto Library into my build pipeline.

The SJCL has its own build process using configuration for inclusion of given features, makefiles, etc, and doesn't use standard CommonJS or ES6 export functionality. Rather than have compilation be part of my build pipeline, I decided it would be nicer if I could wrap their files at build time to create proper JS modules.

SJCL Example

This is how I used the jswrap-brunch plugin to suit my needs of combining and wrapping the SJCL into a more modern module:

• Install jswrap-brunch plugin as `npm install

• Enable it as an npm compiler in brunch-config.js:

  // in brunch-config.js
  
  npm: {
    compilers: ["jswrap-brunch"],
    ...
  }

  Note that this used to be under the plugins.npm key which is now deprecated, despite the brunch documentation.

• Set up the following rules for the plugin:

  // in brunch-config.js
  
  plugins: {
    jsWrap: {
      wrappers: [
        {
          wrap: data => `
            ${data}
            module.exports = sjcl;
          `,
          match: /node_modules\/sjcl\/core\/sjcl\.js$/,
          halt: true
        },
        {
          wrap: data => `
            (function(sjcl) {
            ${data}
            })(require("./sjcl"));
          `,
          match: /node_modules\/sjcl\/core\/.*\.js$/
        }
      ]
    },
    ...
  }

• Create a manifest javascript file in my project code:

  // js/sjcl-wrapper.js
  
  import sjcl from "sjcl/core/sjcl";
  import "sjcl/core/aes"; // side effects on core sjcl module
  import "sjcl/core/cbc";
  // ... etc ...
  
  export default sjcl;

• Now you can import and interact with "custom builds" of the SJCL without actually engaging with its build pipeline.

License

MIT, go nuts.