feat: adding an option to configure a default value to empty values (#766)

Author: anandtiwary

projects/common/src/utilities/formatters/string/display-string.pipe.ts

@@ -5,7 +5,7 @@ import { displayString } from './string-formatter';
   name: 'htDisplayString'
 })
 export class DisplayStringPipe implements PipeTransform {
-  public transform(value: unknown): string {
-    return displayString(value);
+  public transform(value: unknown, defaultValueOnEmpty: string = '-'): string {
+    return displayString(value, defaultValueOnEmpty);
   }
 }

projects/common/src/utilities/formatters/string/string-formatter.test.ts

@@ -16,6 +16,21 @@ describe('String formatter', () => {
     expect(displayString(false)).toBe('false');
   });
 
+  test('can convert to display string with default empty value', () => {
+    // tslint:disable-next-line: no-null-keyword
+    expect(displayString(null, 'none')).toBe('none');
+    expect(displayString('null', 'none')).toBe('none');
+    expect(displayString(undefined, 'none')).toBe('none');
+    expect(displayString('', 'none')).toBe('');
+    expect(displayString('value', 'none')).toBe('value');
+    expect(displayString(15, 'none')).toBe('15');
+    expect(displayString({}, 'none')).toBe('Object');
+    expect(displayString([undefined], 'none')).toBe('[none]');
+    expect(displayString(() => 'hi', 'none')).toBe('Function');
+    expect(displayString(Symbol('test symbol'), 'none')).toBe('Symbol(test symbol)');
+    expect(displayString(false, 'none')).toBe('false');
+  });
+
   test('creates string array correctly from comma separated list', () => {
     expect(getStringsFromCommaSeparatedList('first,second,   third   ')).toEqual(
       expect.arrayContaining(['first', 'second', 'third'])

projects/common/src/utilities/formatters/string/string-formatter.ts

@@ -1,13 +1,15 @@
-export const displayString = (provided?: unknown): string => {
+export const displayString = (provided?: unknown, defaultValueOnEmpty: string = '-'): string => {
   if (provided === null || provided === 'null') {
-    return '-';
+    return defaultValueOnEmpty;
   }
 
   switch (typeof provided) {
     case 'object':
-      return Array.isArray(provided) ? `[${provided.map(displayString).join(', ')}]` : 'Object';
+      return Array.isArray(provided)
+        ? `[${provided.map(value => displayString(value, defaultValueOnEmpty)).join(', ')}]`
+        : 'Object';
     case 'undefined':
-      return '-';
+      return defaultValueOnEmpty;
     case 'function':
       return 'Function';
     case 'string':