Java8-style chainable comparators for Javascript
In working with JS, I've run across situations where I need multi-key sorting in my Backbone collections -- which can sort themselves using the same type of comparator function as Array.prototype.sort expects.
When Java 8 rolled out, it brought with it some useful enhancements to the existing Comparator interface to allow chaining comparators for multi-attribute sort like this:
people.sort(
Comparator.comparing(Person::getLastName)
.thenComparing(Person::getFirstName)
);I really liked that approach, so I brought that into Javascript with the same(ish) syntax. That's this library.
Directly translating our above Java 8 code, we could do the following:
/* Demo data */
var people = [
{lastName: "Baggins", firstName: "Frodo"},
{lastName: "Gamgee", firstName: "Samwise"},
{lastName: "Baggins", firstName: "Bilbo"}
];
sortedPeople = people.sort(Comparators.comparing("lastName").thenComparing("firstName"));
/* sortedPeople is now:
[
{lastName: "Baggins", firstName: "Bilbo"},
{lastName: "Baggins", firstName: "Frodo"},
{lastName: "Gamgee", firstName: "Samwise"},
];
*/For more examples, see the tests in test/comparators.spec.js.
It works in the browser without a module system, as a CommonJS module, and as an AMD module.
The simplest (but global-namespace-polluting) way to use it is to include comparators.js in a script tag:
<script type="text/javascript" src="comparators.min.js"></script>In node/CommonJS loaders, just require it (it's available on NPM as comparators):
var Comparators = require("comparators").default; // the .default is necessary because of how Typescript compiles to commonjsIt works similarly in AMD loaders (require.js used in the below example):
require(['comparators.min'], function(Comparators){
/* Do a thing! */
});Comparators.js is made available under the MIT License (Quick summary of it here)
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