1.0.8 • Public • Published

Bootstrap Pagelet

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This Pagelet is responsible for bootstrapping the client side of BigPipe and keeping state on the child pagelet queue. By default the Bootstrap Pagelet is provided with BigPipe. However, if you require a custom Bootstrap you can extend this Pagelet.


The boostrap Pagelet is distributed through the node package manager (npm).

npm install --save bootstrap-pagelet


Got stuck? Or can't wrap your head around a concept or just want some feedback, we got a dedicated IRC channel for that on Freenode:

  • IRC Server:
  • IRC Room: #bigpipe

Still stuck? Create an issue. Every question you have is a bug in our documentation and that should be corrected. So please, don't hesitate to create issues, many of them.


In this example the Bootstrap Pagelet is extended with a custom view. For instance, if you want to use a custom layout or have several repeating pagelets that always need to be added. BigPipe will automatically discover this extended version if it is provided to BigPipe alongside the other pagelets.

'use strict';
// Extend the Bootstrap Pagelet with a custom view.
var Bootstrap = require('bootstrap-pagelet').extend({
  view: '/path/to/my/custom-view.html'
// Initialise BigPipe server.
var pipe = require('bigpipe').createServer(2000, {
  pagelets: [ bootstrap, ... ]


The following methods are available on the bootstrap instance. Most are only used internally. There is rarely a reason to call these methods.

new Bootstrap()

public, returns Pagelet.

The bootstrap constructor expects several options to be provided, these include: queue, mode, req, res and pipe. The last option is a reference to the BigPipe instance, mainly to ensure the same Temper instance is re-used. All code examples assume your file is setup as:

'use strict';
var Bootstrap = require('bootstrap-pagelet');
  , bootstrap = new Bootstrap({ options });


public, returns string.

Generates the HTML from the values on the pagelet. The properties in bootstrap.keys are provided to the template parser.

var html = bootstrap.render();


private, returns Pagelet.

Push a chunk of HTML on the queue to be flushed. This function will also decrease the internal counter of the number of flushed pagelets. By default the counter is decreased with 1, but a specific Number can be provided as well.

bootstrap.queue('chunk of html', 2);


private, returns Pagelet.

Concatenates all values in the bootstrap._queue and writes the Buffer with the appropriate charset to the response. This function has a fallback for older Node.JS versions to ensure flush is always emitted.

var emit = bootstrap.once('flush', function (error) {
  // Result of the write to response.


The library makes use the diagnostics module from Pagelet. To display the bootstrap Pagelet specific debug messages, supply the following before running the program or

DEBUG=pagelet:bootstrap node ...


Tests are automatically run on Travis CI to ensure that everything is functioning as intended. For local development we automatically install a pre-commit hook that runs the npm test command every time you commit changes. This ensures that we don't push any broken code in to this project.

To run tests locally, make sure the development dependencies are installed.

npm test
npm run coverage


Bootstrap-pagelet is released under MIT.

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npm i bootstrap-pagelet

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