What is comparator?

sebastianbergmann/comparator — explained in plain English

Analysis updated 2026-06-22

★ 7,052PHPAudience · developerComplexity · 2/5Setup · easy

Mindmap

mindmap
  root((comparator))
    What it does
      Value equality checks
      Type-aware comparison
      Failure exceptions
    Supported types
      Objects
      DateTime
      Arrays
      Primitives
    Tech stack
      PHP
      Composer
    Use cases
      Testing frameworks
      PHPUnit dependency
      Custom assertions

mindmap root((comparator)) What it does Value equality checks Type-aware comparison Failure exceptions Supported types Objects DateTime Arrays Primitives Tech stack PHP Composer Use cases Testing frameworks PHPUnit dependency Custom assertions

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What do people build with it?

USE CASE 1

Use it as a dependency to add accurate value comparison to a PHP testing framework or assertion library

USE CASE 2

Compare two DateTime objects from different time zones and verify they represent the same moment in time

USE CASE 3

Handle equality checks for complex PHP objects and arrays in test assertions without writing custom comparison logic

What is it built with?

PHPComposer

How does it compare?

	sebastianbergmann/comparator	php-fig/http-message	mongodb/laravel-mongodb
Stars	7,052	7,051	7,079
Language	PHP	PHP	PHP
Setup difficulty	easy	easy	moderate
Complexity	2/5	2/5	3/5
Audience	developer	developer	developer

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · easy Time to first run · 5min

So what is it?

sebastianbergmann/comparator is a PHP library that provides tools for checking whether two PHP values are equal to each other. It handles the full range of PHP value types, including objects, dates, arrays, and primitive values, and is designed to determine equality in a meaningful way rather than just checking whether two things are identical references. The library is primarily used as a dependency inside testing frameworks and similar tools rather than being called directly in application code. The most common use of this library is inside PHPUnit, the widely used PHP testing framework also maintained by the same author. To install it, you add the package using Composer, which is the standard dependency manager for PHP projects. If you only need the library during development to run tests, you can install it as a development-only dependency using the --dev flag. The README includes a short code example showing how to compare two DateTime objects. You create a Factory instance, ask it for a comparator appropriate for the two values you want to compare, and then call assertEquals on that comparator. If the values are equal the comparison passes silently. If they differ, the comparator throws a ComparisonFailure exception that contains information about how the two values differ. In the example, two date objects representing the same moment in different time zones are compared, and because the underlying moment in time is the same, they are treated as equal. The library has continuous integration testing and code coverage reporting set up, indicating it is actively maintained.

Copy-paste prompts

Prompt 1

Using sebastianbergmann/comparator in PHP, write code to compare two DateTime objects in different time zones and catch the ComparisonFailure exception if they differ.

Prompt 2

How do I install sebastianbergmann/comparator with Composer and use the Factory to compare two custom PHP objects for equality?

Prompt 3

I'm building a PHPUnit extension. Show me how to use the comparator Factory to find the right comparator for two objects of the same class and run the comparison.

Frequently asked questions