Neural Processing Mechanisms


    0.0.4 • Public • Published


    Grunt task for testing page performance using PhantomJS, a headless WebKit browser.

    Getting Started

    Install this grunt plugin next to your project's [grunt.js gruntfile] with: npm install grunt-yslow --save-dev

    Then add this line to your project's grunt.js gruntfile:



    All config must be specified in your Gruntfile.js under the task name yslow.


    • thresholds (object) - An object specifying the global thresholds to test against. These can be overridden by higher specificity against inside the files section below.
      • weight (number) - The maximum page weight allowed (kb).
      • speed (number) - The maximum load time of the page allowed (ms).
      • score (number) - The minimum YSlow performance score (out of 100) required.
      • requests - The maximum number of requests the page is allowed to send on load.
    • yslowOptions (object) - An object specifying any additional parameters for Yslow to use when running the test. This can be overridden below, like thresholds.
      • userAgent (string) - The User-Agent to present to the server
      • cdns (array of strings) - A list of additional hostnames for Yslow to accept as a Content Delivery Network
      • viewport (string) - the size of the viewport in the form WxH, where W is the width and H is the height
      • headers (object) - an object where keys are the header names and values are the values of additional headers to add to the request
    • files (object) - An array of objects, specifying a seperate page to test. Generally this is wrapped inside a named sub-task, such as the 'pages' task in the example below.
      • src (string) - The absolute url to test.
      • thresholds (object) - Any overrides to the global thresholds for this page.
      • yslowOptions (object) - Any overrides to the global Yslow Options for this page.

    Example Grunt Task

    yslow: {
      options: {
        thresholds: {
          weight: 180,
          speed: 1000,
          score: 80,
          requests: 15
      pages: {
        files: [
            src: ''
            src: '',
            thresholds: {
              weight: 100


    npm i grunt-yslow

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