What is the module injector (module injector)?

Module injector is an injector created for a specific module or a section of the application. It lives inside the application but below the root injector in the hierarchy.

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#How it works:

• if Angular does not find a dependency in the module injector, it goes up the chain, to the root injector;
• if a dependency is registered only in the module, it is available only within that module.

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#Example:

Here UserService is registered in the injector of AdminModule. It will only be available to the components, directives, and services of that module.

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#Why it is needed:

• to isolate services within a specific part of the application;
• to avoid conflicts between identical dependencies in different modules;
• to allow separate instances of services for each section.

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Summary: A module injector is a local dependency container that manages services only within its own module and interacts with the root injector through the hierarchy.