Pseudocode - Custom Saga Flow

index.js

const flow1 = new SagaFlow('name')

flow1.run()
/*
output: 
call api:  name
dispatch: SUCC_GET_MAME im response
*/

//--------------------------------------------------------------------//

const flow2 = new SagaFlow()
flow2
.callapi(()=>api('custom get book api',false))
.ok(res=>action.succ_get_book(res))
.fail(res=>action.fail_get_book(res))
.callapi(()=>api('custom get name api',true))
.ok(res=>action.succ_get_name(res))
.fail(res=>action.fail_get_name(res))

flow2.run()
/*
output: 
call api:  custom get book api
dispatch: FAIL_GET_BOOK im response
call api:  custom get name api
dispatch: SUCC_GET_MAME im response
*/

SagaFlow.js

const action = {
  succ_get_name : res=>console.log('dispatch: SUCC_GET_MAME',res),
  fail_get_name : res=>console.log('dispatch: FAIL_GET_MAME',res),
  succ_get_book : res=>console.log('dispatch: SUCC_GET_BOOK',res),
  fail_get_book : res=>console.log('dispatch: FAIL_GET_BOOK',res),
}

function api(param,result=true) {
  console.log('call api: ', param)
  return {body:'im response', result}
}

class SagaFlow {
  
  constructor(key){
    if(key) this.key = key
    this.flow = []
    this.res = null
    this.incall = false
  }
  
  addflow(type,func){
    this.flow.push({type,func})
  }
  
  ok(func){
    this.addflow('ok',func)
    return this
  }
  fail(func){
    this.addflow('fail',func)
    return this
  }
  callapi(func){
    this.addflow('call',func)
    return this
  }
  run(){
    if(this.key && this.flow.length==0){
      this
      .callapi(()=>api(this.key))
      .ok(res=>action['succ_get_'+this.key](res))
      .fail(res=>action['fail_get_'+this.key](res))
    }
    
    while(!!this.flow){
      this.item = this.flow.shift()
      if(!this.item) break;
      switch(this.item.type){
          case 'ok':
            if(this.res.result && this.incall) {
              this.item.func(this.res.body)
              this.incall = false
            }
            break;
          case 'fail':
            if(this.res.result===false && this.incall) {
              this.item.func(this.res.body)
              this.incall = false
            }
            break;
          case 'call':
            this.res = this.item.func(this.key)
            this.incall = true
            break;
          default:
            continue;
      }
    }
    
  }
  
}