transform keys and text service

src/app/widget-modules/pipes/key-translator/key-translator.module.ts

@@ -0,0 +1,16 @@
+import {NgModule} from '@angular/core';
+import {CommonModule} from '@angular/common';
+import {KeyPipe} from './key.pipe';
+
+
+@NgModule({
+  declarations: [KeyPipe],
+  exports: [
+    KeyPipe
+  ],
+  imports: [
+    CommonModule
+  ]
+})
+export class KeyTranslatorModule {
+}

src/app/widget-modules/pipes/key-translator/key.pipe.spec.ts

@@ -0,0 +1,8 @@
+import {KeyPipe} from './key.pipe';
+
+describe('KeyPipe', () => {
+  it('create an instance', () => {
+    const pipe = new KeyPipe();
+    expect(pipe).toBeTruthy();
+  });
+});

src/app/widget-modules/pipes/key-translator/key.pipe.ts

@@ -0,0 +1,13 @@
+import {Pipe, PipeTransform} from '@angular/core';
+import {scaleMapping} from '../../../modules/songs/services/key.helper';
+
+@Pipe({
+  name: 'key'
+})
+export class KeyPipe implements PipeTransform {
+
+  transform(key: string): string {
+    return scaleMapping[key];
+  }
+
+}