Node.js: uri-collection
Scott Ivey -> http://www.scivey.net
An immutable list container for URIs, with chaining methods for filtering and manipulation. Built on top of URIjs and Underscore.
All operations return new collections, leaving the original collections and their elements intact. Filter and search operations like findWhere are modified to accomodate URIjs' interface, e.g. comparing against methods instead of properties where appropriate.
The public API is well-documented, and each method is covered by its own test suite. Each includes tests to verify immutability of existing collections.
Overview
URICollections have methods matching most of the Underscore Collection and Array APIs. Most of these methods proxy to the corresponding Underscore functions at some point, with additional logic to ensure immutability, produce sensible return types, and convert list/collection convenience functions into forms that are reasonable for URIjs' interface.
####Immutability All collections are immutable, even when normally mutating methods are used while iterating over collection elements. This is achieved by cloning the collection elements behind the scenes before they're passed to the iterating function.
var URICollection = require("uri-collection");
var urls = [
"http://www.justcats.net/fuzz",
"http://www.reddit.com/r/alsocats",
"http://www.foxnews.com/nospinzone"
];
var collection1 = new URICollection(urls);
var collection2 = collection1.map( function(oneUrl) {
oneUrl.domain("google.com");
});
console.log( collection2.toString() );
// [ "http://www.google.com/fuzz",
// "http://www.google.com/r/alsocats",
// "http://www.google.com/nospinzone" ]
// the first collection's elements aren't modified,
// even though the operation was performed on object
// references.
console.log( collection1.toString() );
// [ "http://www.justcats.net/fuzz",
// "http://www.reddit.com/r/alsocats",
// "http://www.foxnews.com/nospinzone" ]####Sensible Return Types
When the corresponding Underscore function always returns a single list element, a URICollection method will return a cloned URIjs instance.
In cases where the Underscore method returns an array, the return type depends on the type of the first array element. If the first element is a URIjs instance, the array is wrapped in a new URICollection before being returned. If it's any other type, the raw array is returned. This is in line with the results reasonably expected from the operations in question, e.g. :
var URICollection = require("uri-collection");
var assert = require("assert");
var urls = [
"http://www.thundercats.org/nostalgia",
"http://www.garmentdistrict.com/district/not.html",
"http://www.reddit.com/r/probablymorecats"
];
var collection1 = new URICollection(urls);
var collection2 = collection1.map( function(oneUrl) {
oneUrl.tld("net");
// calling #tld("net") mutates a URI instance,
// changing its TLD to ".net"
});
var domainArray = collection1.map( function(oneUrl) {
oneUrl.domain();
// calling #domain() without parameters returns
// the URI's domain as a string
});
assert(collection2 instanceof URICollection); // true
assert(domainArray instanceof Array); // trueAbove, calling URI#domain() on each element returns a plain array because the #domain() method returns a string. Calling URI#tld("net") on each element returns a new URICollection because the method returns a mutated URIjs instance.
The #first(n) and #last(n) methods follow the convention of Underscore's matching functions: where n is 1 or null, a single element (URIjs instance) is returned, and where n >= 2, a new URICollection is returned.
####Adaptations for URIjs' Interface
Many Underscore convenience methods are intended for plain Javascript objects or arrays - e.g. the object methods #where() and #pluck() are suited to handling properties from normal objects, but not to more complicated objects with data accessed via prototype methods.
URIjs instances have methods where the names might suggest properties. E.g. instead of a property, uri.domain is a getter/setter method which gets when called with no arguments and sets when called with a string. The adapted methods on URICollection instances take this into account, so methods like #pluck(propertyName) work the same way:
var URICollection = require("uri-collection");
var urls = [
"http://www.PepsiLovesYourDemographic.com",
"http://www.burgerking.com/HealthyEatsAtThePalace",
"http://www.frogenthusiasts.net"];
var collection = new URICollection(urls);
var domains = collection.pluck("domain");
console.log(domains);
// ["PepsiLovesYourDemographic.com", "burgerking.com", "frogenthusiasts.net"]
This is also true of the #where() and #findWhere() methods, each of which take an object of key-value pairs to match in the collection. The adapted URICollection methods know to use the named keys as methods of their elements, so this works:
// same collection as above
var burgerLink = collection.findWhere({domain: "burgerking.com"});
console.log( burgerLink.toString() );
// "http://www.burgerking.com/HealthyEatsAtThePalace"
These and the other methods are fully documented on the API page.
Installation
npm install uri-collection
GitHub
https://github.com/scivey/uri-collection
Contact
License
MIT License (MIT)
Copyright (c) 2013 Scott Ivey, scott.ivey@gmail.com
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.