Can I return built-in pipe?

Question

I have a question about angular2 pipe. I want to get pipes as return value depending on schema:string. I think 2 way to get it, but both are not working.

page.html

<p>{{value | getSchema(value, schema)}}</p>

page.ts

getSchema(value, schema){
    if(schema == 'Currency'){
        return "currency: 'USD':true";
    } else if(schema == 'Number'){
        return 'number';
    }
}

or

page.html

<p>{{getSchema(value, schema)}}</p>

page.ts

getSchema(value, schema){
    if(schema == 'Currency'){
        return value + "| currency: 'USD':true";
    } else if(schema == 'Number'){
        return value + '| number';
    }
}

is there any ideas? Thanks.

Why not put the switch logic inside a pipe that takes arguments instead? It will be clearer and probably not as bad performance wise. — masimplo, Nov 25 '16 at 20:14

Günter Zöchbauer · Accepted Answer · 2016-11-28T17:38:27.370

2

You can use a custom pipe that calls to another pipe depending on the parameter

@Pipe({name: 'genericPipe'})
class MyPipe {
  constructor(private currPipe:CurrencyPipe, private numberPipe:NumberPipe) {}
  transform(value, schema) {
    if(schema == 'Currency') {
      return this.currPipe.transform(value);
    } else {
      return this.numberPipe.transform(value);
    }
  }
}

<p>{{value | genericPipe:schema}}</p>

edited Nov 28 '16 at 17:38

answered Nov 25 '16 at 20:31

Günter Zöchbauer

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Can I return built-in pipe?

1 Answers1