feat: introduce where_exp filter from Jekyll

docs/source/_data/sidebar.yml

@@ -88,6 +88,7 @@ filters:
   url_decode: url_decode.html
   url_encode: url_encode.html
   where: where.html
+  where_exp: where_exp.html
 
 tags:
   overview: overview.html

docs/source/filters/overview.md

@@ -12,7 +12,7 @@ Categories | Filters
 Math | plus, minus, modulo, times, floor, ceil, round, divided_by, abs, at_least, at_most
 String | append, prepend, capitalize, upcase, downcase, strip, lstrip, rstrip, strip_newlines, split, replace, replace_first, replace_last,remove, remove_first, remove_last, truncate, truncatewords
 HTML/URI | escape, escape_once, url_encode, url_decode, strip_html, newline_to_br
-Array | slice, map, sort, sort_natural, uniq, where, group_by, group_by_exp, find, find_exp, first, last, join, reverse, concat, compact, size, push, pop, shift, unshift
+Array | slice, map, sort, sort_natural, uniq, where, where_exp, group_by, group_by_exp, find, find_exp, first, last, join, reverse, concat, compact, size, push, pop, shift, unshift
 Date | date
 Misc | default, json, raw
 

docs/source/filters/where_exp.md

@@ -0,0 +1,37 @@
+---
+title: where_exp
+---
+
+{% since %}v10.12.0{% endsince %}
+
+Select all the objects in an array where the expression is true. In this example, assume you have a list of products and you want to show your kitchen products separately. Using `where_exp`, you can create an array containing only the products that have a `"type"` of `"kitchen"`.
+
+Input
+```liquid
+All products:
+{% for product in products %}
+- {{ product.title }}
+{% endfor %}
+
+{% assign kitchen_products = products | where_exp: "item", "item.type == 'kitchen'" %}
+
+Kitchen products:
+{% for product in kitchen_products %}
+- {{ product.title }}
+{% endfor %}
+```
+
+Output
+```text
+All products:
+- Vacuum
+- Spatula
+- Television
+- Garlic press
+
+Kitchen products:
+- Spatula
+- Garlic press
+```
+
+[truthy]: ../tutorials/truthy-and-falsy.html

docs/source/zh-cn/filters/overview.md

@@ -12,7 +12,7 @@ LiquidJS 共支持 40+ 个过滤器，可以分为如下几类：
 数学 | plus, minus, modulo, times, floor, ceil, round, divided_by, abs, at_least, at_most
 字符串 | append, prepend, capitalize, upcase, downcase, strip, lstrip, rstrip, strip_newlines, split, replace, replace_first, replace_last, remove, remove_first, remove_last, truncate, truncatewords
 HTML/URI | escape, escape_once, url_encode, url_decode, strip_html, newline_to_br
-数组 | slice, map, sort, sort_natural, uniq, where, group_by, group_by_exp, find, find_exp, first, last, join, reverse, concat, compact, size, push, pop, shift, unshift
+数组 | slice, map, sort, sort_natural, uniq, where, where_exp, group_by, group_by_exp, find, find_exp, first, last, join, reverse, concat, compact, size, push, pop, shift, unshift
 日期 | date
 其他 | default, json
 

docs/source/zh-cn/filters/where_exp.md

@@ -0,0 +1,37 @@
+---
+title: where_exp
+---
+
+{% since %}v10.12.0{% endsince %}
+
+从数组中选择所有表达式值为真的对象。下面的例子中，假设你要从产品列表中筛选出来厨房用品。利用 `where_exp` 可以创建一个只包含 `"type"` 为 `"kitchen"` 的列表。
+
+Input
+```liquid
+All products:
+{% for product in products %}
+- {{ product.title }}
+{% endfor %}
+
+{% assign kitchen_products = products | where_exp: "item", "item.type == 'kitchen'" %}
+
+Kitchen products:
+{% for product in kitchen_products %}
+- {{ product.title }}
+{% endfor %}
+```
+
+Output
+```text
+All products:
+- Vacuum
+- Spatula
+- Television
+- Garlic press
+
+Kitchen products:
+- Spatula
+- Garlic press
+```
+
+[truthy]: ../tutorials/truthy-and-falsy.html

src/filters/array.ts

@@ -102,6 +102,16 @@ export function * where<T extends object> (this: FilterImpl, arr: T[], property:
   })
 }
 
+export function * where_exp<T extends object> (this: FilterImpl, arr: T[], itemName: string, exp: string): IterableIterator<unknown> {
+  const filtered: unknown[] = []
+  const keyTemplate = new Value(stringify(exp), this.liquid)
+  for (const item of toArray(arr)) {
+    const value = yield keyTemplate.value(new Context({ [itemName]: item }))
+    if (value) filtered.push(item)
+  }
+  return filtered
+}
+
 export function * group_by<T extends object> (arr: T[], property: string): IterableIterator<unknown> {
   const map = new Map()
   arr = toArray(arr)

test/integration/filters/array.spec.ts

@@ -476,6 +476,28 @@ describe('filters/array', function () {
         `)
     })
   })
+  describe('where_exp', function () {
+    const products = [
+      { title: 'Vacuum', type: 'living room' },
+      { title: 'Spatula', type: 'kitchen' },
+      { title: 'Television', type: 'living room' },
+      { title: 'Garlic press', type: 'kitchen' },
+      { title: 'Coffee mug', available: true },
+      { title: 'Limited edition sneakers', available: false },
+      { title: 'Boring sneakers', available: true }
+    ]
+    it('should support filter by exp', function () {
+      return test(`{% assign kitchen_products = products | where_exp: "item", "item.type == 'kitchen'" %}
+        Kitchen products:
+        {% for product in kitchen_products -%}
+        - {{ product.title }}
+        {% endfor %}`, { products }, `
+        Kitchen products:
+        - Spatula
+        - Garlic press
+        `)
+    })
+  })
   describe('group_by', function () {
     const members = [
       { graduation_year: 2003, name: 'Jay' },