PHP WeakMap::offsetGet() Method: Usage and Examples

Fetches the metadata associated with an object key.

The examples focus on the operation itself, including the important distinction: offsetSet creates or updates the association.

What It Does

Use the examples below to observe the behavior on a small dataset before extending it to application code.

Syntax and Return Value

WeakMap::offsetGet($object): mixed

The displayed signature describes the API or identifies any correction or optional dependency. When a parameter is optional, supply it only when the task requires it.

Parameters

• object: required.

Declared return type: mixed. Read the behavior notes for important cases such as empty collections and destructive iteration.

Example 1: Basic Use

The map tracks an object only while another strong reference keeps it alive; keys use identity rather than a name string.

<?php
$user = (object) ["name" => 'Ari'];
$other = (object) ["name" => "guest"];
$metadata = new WeakMap();
$metadata[$user] = ["score" => 2];
echo $metadata->offsetGet($user)["score"];

Output from a successful local PHP 8.4 run:

2

Example 2: Checking Behavior

The map tracks an object only while another strong reference keeps it alive; keys use identity rather than a name string.

<?php
$user = (object) ["name" => 'Bo'];
$other = (object) ["name" => "guest"];
$metadata = new WeakMap();
$metadata[$user] = ["score" => 3];
echo $metadata->offsetGet($user)["score"];

Output from a successful local PHP 8.4 run:

3

Example 3: Practical Example

The map tracks an object only while another strong reference keeps it alive; keys use identity rather than a name string.

<?php
$user = (object) ["name" => 'Cam'];
$other = (object) ["name" => "guest"];
$metadata = new WeakMap();
$metadata[$user] = ["score" => 4];
echo $metadata->offsetGet($user)["score"];

Output from a successful local PHP 8.4 run:

4

Important Behavior and Edge Cases

A missing key throws an Error; test offsetExists first.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Fetches the metadata associated with an object key.
• A missing key throws an Error; test offsetExists first.
• offsetSet creates or updates the association.

Use WeakMap::offsetGet when its documented behavior matches the problem. Test the relevant edge cases in your own runtime before deploying it.