Helps front-end developers to reach a good quality good performances, based on phantomas and grunt-phantomas.
npm install grunt-devperfHelps front-end developers to reach a good quality and good performances, based on phantomas and grunt-phantomas.
Day after day, while working on your project, keep an eye on performance metrics and get warnings for things you should optimize.
Use this minimalist installation if you just want to launch some quick tests.
You need NodeJS v0.8 or higher. If you don't have it, go to http://nodejs.org and grab the latest version.
1) Create a directory for your grunt-devperf installation, anywhere you want. Let's call it devperf:
``shell`
mkdir devperf
cd devperf
2) Install Grunt globally:
`shell`
npm install grunt-cli -g
3) Install grunt-devperf locally:
`shell`
npm install grunt-devperf
4) Copy the example Gruntfile.js to the root of your devperf directory:`shell`
cp node_modules/grunt-devperf/demo/smallest-config/Gruntfile.js ./
5) Then edit this copy of Gruntfile.js to insert your own list of URLs.
It's done! You can launch your first test with this command:
`shell`
grunt
This plugin requires Grunt ~0.4.4.
Install the plugin:
`shell`
npm install grunt-devperf --save-dev
Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:
`js`
grunt.loadNpmTasks('grunt-devperf');
I recommand using it as a part of your Continuous Integration system, but you can also simply use it locally while developping.
to the data object passed into grunt.initConfig().`js
grunt.initConfig({
devperf: {
options: {
urls: [
'http://www.google.com'
]
}
}
});
`$3
#### options.urls
Type:
Default value: The list of URLs you want to test. Don't forget the protocol (http:// or https://), even on localhost.
#### options.numberOfRuns
Type:
Default value: The number of times you want phantomas to call each page.
A higher number of runs could give a better accuracy, but note that they are run in parallel and that your machine's bandwith may suffer.
#### options.timeout
Type:
Default value: The time after which phantomas should cancel a run.
#### options.openResults
Type:
Default value: Automatically opens the browser on the results page when the devperf task is finished.
#### options.resultsFolder
Type:
Default value: This is the folder where the results will be generated, including grunt-phantomas reports.
It can be relative to your project:
(you might want to add this folder to your .gitignore file).
Or it can be anywhere else in your file system: /var/www/devperf
$3
In this example, several Urls are tested
js
grunt.initConfig({
devperf: {
options: {
urls: [
'http://www.google.com',
'http://www.yahoo.com',
'http://www.github.com',
'http://www.facebook.com'
],
numberOfRuns: 5,
timeout: 120,
openResults: true,
resultsFolder: './devperf'
}
}
});
`
Then, open the file with your browser to see the results. It is located in the results folder (./devperf/by default).
Results snapshot:
!grunt-devperf example results
About the results:
- Yes it looks like a console but it's a web page!
- Some metrics might have decimals, because they are averages of multiple runs.
- The link to the grunt-phantomas report will give you tons of details, very helpful for debugging.
- The files size are not reliable (sometimes gzipped, sometimes not). Check issue #6.
$3
#### Default list of warnings
When a metric is greater than the limit, the message is displayed.
Metric | Limit | Message
--------------------------|:-------:|--------------------------------------------------------------------
requests | 200 | Too many requests, i guess your site is slow, isn't it?
cssCount | 6 | Too many CSS files, use concatenation
jsCount | 12 | Too many JS files, use concatenation
imageCount | 30 | Too many images, use lazyloading
smallImages | 20 | Too many small images (<2kB), build sprites
imageSize | 512000 | Total image size (bytes) is too high, try image optimisation
webfontCount | 4 | Too many custom fonts, tell the designer you don't want that
notFound | 0 | Number of 404 errors
multipleRequests | 1 | Some static assets are requested multiple times
imagesWithoutDimensions | 5 | Number of images without dimensions
commentsSize | 1000 | Reduce size of comments in HTML
whiteSpacesSize | 8000 | Reduce the number of whitespaces in HTML
DOMelementsCount | 2000 | Reduce the number of DOM elements
documentWriteCalls | 0 | Remove all document.write() calls
jsErrors | 0 | Number of Javascript errors
consoleMessages | 0 | Remove console.log or console.whatever
DOMqueries | 200 | Reduce number of DOM queries
DOMqueriesDuplicated | 30 | Many duplicated DOM queries, try to save results into variables
DOMinserts | 100 | Reduce number of DOM insertions
jQuerySizzleCalls | 300 | Reduce number of Sizzle calls (= jQuery DOM queries)
headersSentSize | 20000 | Reduce size of headers sent (cookies?)
#### Modifying the warnings
In the Gruntfile, you can change any of them by adding a
warnings option this way:`js
grunt.initConfig({
devperf: {
options: {
urls: [
'http://www.google.com'
],
warnings: [
{
// Changing the limit for this variable
variable : "jsErrors",
limit : 42,
},
{
// Changing the message
variable : "jQuerySizzleCalls",
message : "I like this message best"
},
{
// Changing the limit and the message
variable : "DOMelementsCount",
limit : 200,
message: "DOM elements number is my big issue so i reduced the limit"
},
{
// Disabling a warning (-1 is infinite)
variable : "consoleMessages",
limit : -1
},
{
// Adding one of the numerous Phantomas variables not handled by grunt-devperf
variable : "jsonCount",
limit : 5,
message : "I really care about having a small number of JSON requests"
}
]
}
}
});
`You can find the complete list of Phantomas variables and their descriptions here.
If you think one of these variables deserves a warning in grunt-devperf, don't hesitate to open an issue!
$3
#### options.phantomasOptions
Type:
Default value: Use this if you need to send parameters to
. You can find the list of parameters here. You can enable some features such as proxy, authentification or domain blocking.Example:
`js
grunt.initConfig({
devperf: {
options: {
urls: [
'http://www.google.com'
],
phantomasOptions: {
'proxy': 'localhost:8080',
'no-externals': true
}
}
}
});
``