feat: Add support for the Jekyll sample filter (#612)

* Add support for the Jekyll sample filter

See https://jekyllrb.com/docs/liquid/filters

I am sorting the array randomly and then picking the first N items or all items if there is no sample limit.

* Remove incorrect spaces before parens

Typo and copy-paste meet

src/filters/array.ts

@@ -88,3 +88,14 @@ export function uniq<T> (arr: T[]): T[] {
     return true
   })
 }
+
+export function sample<T> (v: T[] | string, count: number | undefined = undefined): T[] | string {
+  v = toValue(v)
+  if (isNil(v)) return []
+  if (!isArray(v)) {
+    v = stringify(v)
+    return [...v].sort(() => Math.random()).slice(0, count).join('')
+  }
+
+  return [...v].sort(() => Math.random()).slice(0, count)
+}

test/integration/filters/array.spec.ts

@@ -104,6 +104,20 @@ describe('filters/array', function () {
       expect(html).toBe('abc')
     })
   })
+  describe('sample', function () {
+    it('should return full array sample', () => test(
+      '{{ "hello,world" | split: "," | sample | size }}',
+      '2'
+    ))
+    it('should return full array sample even if excess count', () => test(
+      '{{ "hello,world" | split: "," | sample: 10 | size }}',
+      '2'
+    ))
+    it('should return partial array sample', () => test(
+      '{{ "hello,world" | split: "," | sample: 1 | size }}',
+      '1'
+    ))
+  })
   describe('size', function () {
     it('should return string length', () => test(
       '{{ "Ground control to Major Tom." | size }}',