fix: sample filter randomness and count=1 case

CHANGELOG.md

@@ -17,6 +17,7 @@
 ### Features
 
 * Add support for the Jekyll sample filter ([#612](https://github.com/harttle/liquidjs/issues/612)) ([ba8b842](https://github.com/harttle/liquidjs/commit/ba8b84245266589e43c0e70d99e12b981d349809))
+* Add support for the Jekyll push filter ([#611](https://github.com/harttle/liquidjs/issues/611))
 * introduce a matrix with latest Ubuntu and macOS to test the build on macOS as well ([82ba548](https://github.com/harttle/liquidjs/commit/82ba54845f4cd4e1e7660c1557e3cfaa22d68924)), closes [#615](https://github.com/harttle/liquidjs/issues/615)
 * precise line/col for tokenization Error, [#613](https://github.com/harttle/liquidjs/issues/613) ([e347e60](https://github.com/harttle/liquidjs/commit/e347e603d76c039cec191d417deab34e7ef1f9a7))
 

src/filters/array.ts

@@ -89,9 +89,11 @@ export function uniq<T> (arr: T[]): T[] {
   })
 }
 
-export function sample<T> (v: T[] | string, count: number | undefined = undefined): (T | string)[] {
+export function sample<T> (v: T[] | string, count = 1): T | string | (T | string)[] {
   v = toValue(v)
   if (isNil(v)) return []
   if (!isArray(v)) v = stringify(v)
-  return [...v].sort(() => Math.random()).slice(0, count)
+  const shuffled = [...v].sort(() => Math.random() - 0.5)
+  if (count === 1) return shuffled[0]
+  return shuffled.slice(0, count)
 }

test/integration/filters/array.spec.ts

@@ -1,6 +1,8 @@
 import { test, render } from '../../stub/render'
+import { Liquid } from '../../../src/liquid'
 
 describe('filters/array', function () {
+  const engine = new Liquid()
   describe('index', function () {
     it('should support index', function () {
       const src = '{% assign beatles = "John, Paul, George, Ringo" | split: ", " %}' +
@@ -97,6 +99,10 @@ describe('filters/array', function () {
       const scope = { val: ['hey'], arg: 'foo' }
       await test('{{ val | push: arg | join: "," }}', scope, 'hey,foo')
     })
+    it('should not change original array', async () => {
+      const scope = { val: ['hey'], arg: 'foo' }
+      await test('{{ val | push: arg | join: "," }} {{ val | push: arg | join: "," }}', scope, 'hey,foo hey,foo')
+    })
     it('should support undefined left value', async () => {
       const scope = { arg: 'foo' }
       await test('{{ notDefined | push: arg | join: "," }}', scope, 'foo')
@@ -126,17 +132,18 @@ describe('filters/array', function () {
     })
   })
   describe('sample', function () {
-    it('should return full array sample', () => test(
-      '{{ "hello,world" | split: "," | sample | size }}',
-      '2'
-    ))
+    it('should return one item if count not specified', async () => {
+      const template = '{{ "hello,world" | split: "," | sample }}'
+      const result = await engine.parseAndRender(template)
+      expect(result).toMatch(/hello|world/)
+    })
     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'
+      '5'
     ))
     it('should sample nil value', () => test(
       '{{ nil | sample: 2 }}',