How to do conditionally something in rxjs pipe?

Issue

Could somebody tell me what is the right syntax for an rxjs pipe with a conditional operation? In this case i would like to do the mapping with the filter, if the enviroment name array lenght is not 1. How can i use an if statement without return? Is there any rxjs operator for this?

environmentName = ['env1', 'env2'];

sourceList$ = this.getSources().pipe(
tap((srcList) => console.log(srcList)), //[["stylesheet","env1-xyz"],["include","cable"],...]
// if(this.environmentName.length!==1){
map((sourceList) => sourceList.filter((scr) => scr[1].startsWith(this.environmentName[0]) || scr[0] === 'include')),
//}
repeatWhen(() => this.sourceListChanged$)
);

Solution

Mentioned iif is not operator. Use e.g. mergeMap to incorporate it into your code:

environmentName = ['env1', 'env2'];

const filterSourceListByEnv1OrInclude = srcList => srcList.filter((scr) => scr[1].startsWith(this.environmentName[0]) || scr[0] === 'include');

sourceList$ = this.getSources().pipe(
  tap((srcList) => console.log(srcList)),
  mergeMap(srcList => iff(
    () => this.environmentName.length !== 1,
    of(filterSourceListByEnv1OrInclude(srcList)),
    of(srcList)
  )),
  repeatWhen(() => this.sourceListChanged$)
);

Or ternary operator could be used instead of iif:

sourceList$ = this.getSources().pipe(
  tap((srcList) => console.log(srcList)),
  mergeMap(srcList => of(this.environmentName.length !== 1
    ? filterSourceListByEnv1OrInclude(srcList)
    : srcList
  )),
  repeatWhen(() => this.sourceListChanged$)
);

Answered By - Lubomir Jurecka