min-filter.js

Minimal filter chain for Node.js and the browser

Install with npm

npm install min-filter

Usage

The filter operates on a min-iterator implementation. This example uses a live-list to demonstrate the usage:

var filter = require('min-filter');
var List   = require('live-list').List;

var l = new List();
l.push({
  fn: function (next) {
    // Do stuff before the next thing ...
    next();
  }
});
l.push({
  fn: function (next, callback) {
    next(function () {
      // Do stuff on the way back ...
      callback();
    });
  },
  scope: this
});

var it = l.iterator();

filter(it, function (err, value) {
  // Done.
});

API

filter(iterator[, scope][[, then], callback])

• iterator: min-iterator that returns objects with filter functions
• scope: The object to use as this in each filter function, if not specified otherwise
• then: A function that is invoked after the last filter called next. Receives an optional callback argument. If a callback is given, it triggers execution of the functions passed to next by the filters.
• callback: A function that is invoked after all processing of all filters, the done function and all callbacks has finished. Receives an error object as the first argument and any additional arguments passed back by the callbacks.

Data structure of objects returns by iterator:

• fn: The filter function
• scope: The scope to use when invoking the filter function. This overrides the scope passed to filter.

Valid argument combinations:

• filter(it, callback): Invokes filters, then callback
• filter(it, then, callback): Invokes filters, calls then after last filter called next, then invokes callback
• filter(it, scope, callback): Invokes filters with given scope, then invokes callback
• filter(it, scope, then, callback): Invokes filters with given scope, calls then after last filter called next, then invokes callback

Browser compatibility

To use this module in a browser, download the npm package and then use Browserify to create a standalone version.

License

MIT