feat: introduce resultToObservable (#195)

src/result/pubcli_api.spec.ts

@@ -1,10 +1,11 @@
-import { Result, fail, ok, result, resultToPromise } from './public_api'
+import { Result, fail, ok, result, resultToPromise, resultToObservable } from './public_api'
 
 describe('result api', () => {
   it('should export', () => {
     expect(fail(Error('Test'))).toBeInstanceOf(Result)
     expect(ok(1)).toBeInstanceOf(Result)
     expect(result(() => true, 1, Error('Test'))).toBeInstanceOf(Result)
     expect(typeof resultToPromise).toEqual('function')
+    expect(typeof resultToObservable).toEqual('function')
   })
 })

src/result/public_api.ts

@@ -4,3 +4,4 @@ export * from './result.interface'
 export * from './transformers/result-to-promise'
 export * from './transformers/try-catch-to-result'
 export * from './transformers/unwrap-result'
+export * from './transformers/result-to-observable'

src/result/transformers/result-to-observable.spec.ts

@@ -0,0 +1,32 @@
+import { fail, ok } from '../result.factory'
+import { resultToObservable } from './result-to-observable'
+
+describe(resultToObservable.name, () => {
+  it('should be ok', done => {
+    const result = ok<string, Error>('hello')
+    const sut = resultToObservable(result)
+
+    sut
+      .subscribe({
+        next: v => {
+          expect(v).toEqual('hello')
+          done()
+        },
+        error: done
+      })
+  })
+
+  it('should be ok', done => {
+    const result = fail<string, Error>(new Error('I failed, sorry.'))
+    const sut = resultToObservable(result)
+
+    sut
+      .subscribe({
+        error: (v: Error) => {
+          expect(v.message).toEqual('I failed, sorry.')
+          done()
+        },
+        next: done
+      })
+  })
+})

src/result/transformers/result-to-observable.ts

@@ -0,0 +1,10 @@
+import { Observable, of, throwError } from 'rxjs'
+import { IResult } from '../result.interface'
+
+export function resultToObservable<TOk, TFail>(result: IResult<TOk, TFail>): Observable<TOk> {
+  if (result.isOk()) {
+    return of(result.unwrap())
+  } else {
+    return throwError(() => result.unwrapFail())
+  }
+}