Angular Interview Test 2025 – 400 Free Practice Questions to Pass the Exam

The key-value pipe in Angular serves a specific purpose by transforming an object or a map into an array of key-value pairs. This functionality is particularly useful when you have an object with properties that you want to iterate over in a template. Instead of directly accessing the properties of an object for display, the key-value pipe allows you to convert that object into a format that is easier to manipulate and display within an Angular template.

When using the key-value pipe, the output becomes an array where each entry is an object with two properties: the key and the value. This makes it simple to use Angular's structural directives, like *ngFor, to loop through and present the data in various forms, improving the flexibility and readability of your UI code.

In contrast, other options mentioned in the question serve different purposes. Serializing an object into a JSON string, validating input values, and notifying changes to observables are distinct operations that do not relate to transforming an object into key-value pairs in the same way that the key-value pipe does.