Vulcanize
Concatenate a set of Web Components into one file
Named for the Vulcanization process that turns polymers into more durable
materials.
Installation
vulcanize
is available on npm. For maximium utility, vulcanize
should be installed globally.
sudo npm install -g vulcanize
This will install vulcanize
to /usr/local/bin/vulcanize
.
Usage
vulcanize index.html
At the simplest, vulcanize
only requires an html file as an argument. The optimized output file will be named
vulcanized.html
.
If you want to control the output name, use the -o
flag
vulcanize -o build.html index.html
Most URLs will be automatically adjusted by the vulcanizer.
Options
--output
, -o
- Output file name (defaults to vulcanized.html)
--verbose
, -v
- More verbose logging
--help
, -v
, -?
- Print this message
--config
--strip
, -s
- Remove comments and empty text nodes
--csp
- Extract inline scripts to a separate file (uses
<output file name>
.js) --inline
- The opposite of CSP mode, inline all assets (script and css) into the document
--inline --csp
- Bundle all javascript (inline and external) into
<output file name>
.js
--abspath
, -p
- Specify site root. Resolve paths to absolute paths based on site root
--no-strip-excludes
- Keep imports excluded from inlining
--version
, -V
- print version information
Config
JSON file for additional options
- Excludes: Remove the selected urls from the vulcanized bundle:
Example Config
{
"excludes": {
"imports": [
"regex-to-exclude"
]
}
}
Example Usage
Say we have three html files: index.html
, x-app.html
, and x-dep.html
.
index.html:
<!DOCTYPE html>
<link rel="import" href="x-app.html">
<x-app></x-app>
x-app.html:
<link rel="import" href="path/to/x-dep.html">
<polymer-element name="x-app">
<template>
<x-dep></x-dep>
</template>
<script>Polymer('x-app')</script>
</polymer-element>
x-dep.html:
<polymer-element name="x-dep">
<template>
<img src="x-dep-icon.jpg">
</template>
<script>
Polymer('x-dep');
</script>
</polymer-element>
Running vulcan on index.html
, and specifying build.html
as the output:
vulcanize -o build.html index.html
Will result in build.html
that appears as so:
<!DOCTYPE html>
<div hidden><polymer-element name="x-dep" assetpath="path/to/">
<template>
<img src="http://www.polymer-project.org/images/logos/p-logo.svg">
</template>
<script>
Polymer('x-dep');
</script>
</polymer-element>
<polymer-element name="x-app" assetpath="">
<template>
<x-dep></x-dep>
</template>
<script>Polymer('x-app')</script>
</polymer-element>
</div>
<x-app></x-app>
Content Security Policy
Content Security Policy, or CSP, is a Javascript security model
that aims to prevent XSS and other attacks. In so doing, it prohibits the use of inline scripts.
To help automate the use of Polymer element registration with CSP, the --csp
flag to vulcan will remove all scripts
from the HTML Imports and place their contents into an output javascript file.
Using the previous example, the output from vulcanize --csp -o build.html index.html
will be
build.html:
<!DOCTYPE html>
<div hidden><polymer-element name="x-dep" assetpath="path/to/">
<template>
<img src="http://www.polymer-project.org/images/logos/p-logo.svg">
</template>
</polymer-element>
<polymer-element name="x-app" assetpath="">
<template>
<x-dep></x-dep>
</template>
</polymer-element>
</div>
<x-app></x-app>
<script src="build.js"></script>
build.js:
Polymer('x-dep');
;
Polymer('x-app')
The JS files can become a bit messy without reformatting, and semi-colons are inserted between script contents as a
precaution.
Stripping whitespace
Vulcanize includes a set of size reducing heuristics to remove unnecessary whitespace and comments in HTML, JS, and CSS.
This can be activated by using the --strip
option.
Using the previous example, the output from vulcanize --csp -o build.html --strip index.html
will be
build.html:
<!DOCTYPE html>
<div hidden><polymer-element name="x-dep" assetpath="path/to/"><template><img src="http://www.polymer-project.org/images/logos/p-logo.svg"></template></polymer-element><polymer-element name="x-app" assetpath=""><template><x-dep></x-dep></template></polymer-element></div>
<x-app></x-app>
<script src="build.js"></script>
Polymer("x-dep");Polymer("x-app");