Similar to Java method references, TypeScript also provides a way to reference functions

Although I am familiar with Java, TypeScript is fairly new to me. In Java, lambda expressions (->) or method references (::) are commonly used to satisfy functional interfaces.

It seems like lambda expressions function similarly in both languages (please correct me if I'm mistaken). However, I'm curious if there is a way to incorporate method references in TypeScript as well?

Suppose we aim to achieve the following:

  this.entryService.getEntries()
    .subscribe(entries => this.listUpdateService.send(entries));

Is it possible to use a function reference instead? There seems to be an issue when attempting the following approach, because send isn't executed within the scope of this.listUpdateService. (By the way, in which scope does it execute?)

  this.entryService.getEntries()
    .subscribe(this.listUpdateService.send);

Answer №1

It is indeed correct that the scope is not referring to this.listUpdateService.

To maintain the appropriate scope, it is common practice to use the bind method.

this.entryService.getEntries()
  .subscribe(this.listUpdateService.send.bind(this.listUpdateService));

Here is a live example in the playground

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