Merge pull request #147 from nextcloud/enh/default-value

Add optional parameter to use as a default

Author: juliusknorr

lib/index.ts

@@ -1,11 +1,15 @@
 /**
  * @param app app ID, e.g. "mail"
  * @param key name of the property
+ * @param fallback optional parameter to use as default value
  * @throws if the key can't be found
  */
-export function loadState<T>(app: string, key: string): T {
+export function loadState<T>(app: string, key: string, fallback?: T): T {
     const elem = <HTMLInputElement>document.querySelector(`#initial-state-${app}-${key}`)
     if (elem === null) {
+        if (fallback !== undefined) {
+            return fallback
+        }
         throw new Error(`Could not find initial state ${key} of ${app}`)
     }
 

test/index.test.js

@@ -4,6 +4,10 @@ test('throw if nothing found', () => {
     expect(() => loadState('test', 'key')).toThrow(new Error("Could not find initial state key of test"))
 })
 
+test('return default if provided', () => {
+    expect(loadState('test', 'key', 'default')).toBe('default')
+})
+
 test('find correct value', () => {
     const input = document.createElement('input')
     input.setAttribute('type', 'hidden')