feat: improve function arrLast

GreatAuk · May 9, 2024 · 13af4ad · 13af4ad
1 parent 2a4e517
commit 13af4ad
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Showing 3 changed files with 6 additions and 3 deletions.
diff --git a/packages/core/src/arrLast.test.ts b/packages/core/src/arrLast.test.ts
@@ -10,6 +10,7 @@ describe('arrLast', () => {
     expect(arrLast(['a', 1, true, /r/g])).toEqual(/r/g)
     expect(arrLast([1])).toBe(1)
     expect(arrLast([])).toBe(undefined)
+    expect(arrLast<string[]>([], 'he')).toBe('he')
   })
   it('should work with readonly arrays', () => {
     const arr = [1, 2, 3, 4, 5] as const

diff --git a/packages/core/src/arrLast.ts b/packages/core/src/arrLast.ts
@@ -14,9 +14,9 @@ type ArrayLast<T extends readonly unknown[]> = T extends readonly [...infer _, i
  * ```
  * @linkcode https://github.com/GreatAuk/utopia-utils/blob/main/packages/core/src/arrLast.ts
  */
-export function arrLast<T extends readonly unknown[]>(arr: T): ArrayLast<T>
-export function arrLast<T extends unknown[]>(arr: T): T[number] {
+export function arrLast<T extends readonly unknown[]>(arr: T, defaultValue?: T[number] | null | undefined): ArrayLast<T>
+export function arrLast<T extends unknown[]>(arr: T, defaultValue?: T[number] | null | undefined): T[number] {
   if (!Array.isArray(arr))
     throw new TypeError('Expected an Array')
-  return arr[arr.length - 1]
+  return arr?.length > 0 ? arr[arr.length - 1] : defaultValue
 }
diff --git a/packages/core/src/capitalize.test.ts b/packages/core/src/capitalize.test.ts
@@ -3,5 +3,7 @@ import { capitalize } from './capitalize'
 describe('capitalize', () => {
   it('should capitalize the first letter of a string', () => {
     expect(capitalize('foo')).toBe('Foo')
+    expect(capitalize('hello world')).toBe('Hello world')
+    expect(capitalize('')).toBe('')
   })
 })