[Verse 1] In Angular apps we need a way To share our logic every day Services hold the business rules Singleton pattern is our tool Injectable decorator marks the class Dependency injection makes it last Provider tree delivers what we need Clean separation plants the seed [Chorus] Services share, HTTP declares Observable streams flow everywhere Inject the client, make the call Reactive patterns handle all S-I-N-G-L-E-T-O-N One instance serves from start to end HTTP client is our friend Data flows that never bend [Verse 2] HTTP client needs import first From common module quench the thirst GET and POST and PUT and DELETE Methods that make our API complete Headers carry information Interceptors transformation Base URL and endpoints combine Request configuration by design [Chorus] Services share, HTTP declares Observable streams flow everywhere Inject the client, make the call Reactive patterns handle all S-I-N-G-L-E-T-O-N One instance serves from start to end HTTP client is our friend Data flows that never bend [Bridge] Error handling with catch error Retry logic when things get terrar Map and filter transform the stream Subscribe to make it all supreme Async pipe in templates clean No memory leaks in the machine Unsubscribe when component dies Keep your application optimized [Verse 3] Business logic lives apart From components that show the art Service methods return observables Data streams that are reliable Constructor injection brings them in Type safety helps us always win Private fields and public methods Encapsulation that never threatens [Chorus] Services share, HTTP declares Observable streams flow everywhere Inject the client, make the call Reactive patterns handle all S-I-N-G-L-E-T-O-N One instance serves from start to end HTTP client is our friend Data flows that never bend [Outro] Reactive patterns guide the way Angular services every day HTTP communication flows That's how full-stack knowledge grows
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