Is it possible to use a pipe in the code?

问题

When I use my custom pipe in a template, it is like this:

{{user|userName}}

And it works well.

Is it possible to use a pipe in the code?

I try to use it like this:

let name = `${user|userName}`;

But it shows

userName is not defined

My alternative way is using db.collection.findOne() manually in the code. But is there any smart way?

回答1:

First declare the pipe in the providers of your module:

import { YourPipeComponentName } from 'your_component_path';

@NgModule({
  providers: [
    YourPipeComponentName
  ]
})
export class YourServiceModule {
}

Then you can use @Pipe in a component like this:

import { YourPipeComponentName } from 'your_component_path';

class YourService {

  constructor(private pipe: YourPipeComponentName) {}

  YourFunction(value) {
    this.pipe.transform(value, 'pipeFilter');
  }
}

回答2:

@Siva is correct. And thanks!

So the way to use the pipe in the component is like this:

let name = new UserNamePipe().transform(user);

Link to another similar question.

来源：https://stackoverflow.com/questions/35159079/is-it-possible-to-use-a-pipe-in-the-code