From e69a51025efa7dec7d60d0067200a1466988ebbc Mon Sep 17 00:00:00 2001
From: Harttle <harttle@harttle.com>
Date: Fri, 22 Apr 2022 00:26:51 +0800
Subject: [PATCH] fix: support integer arithmetic for `divided_by`, closes #465

---
 docs/source/filters/divided_by.md        | 19 ++++++++++++++++++-
 docs/source/zh-cn/filters/divided_by.md  | 19 ++++++++++++++++++-
 src/builtin/filters/math.ts              |  2 +-
 test/e2e/issues.ts                       |  5 +++++
 test/integration/builtin/filters/math.ts |  2 ++
 5 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/docs/source/filters/divided_by.md b/docs/source/filters/divided_by.md
index 88038f748..13fe10228 100644
--- a/docs/source/filters/divided_by.md
+++ b/docs/source/filters/divided_by.md
@@ -26,6 +26,23 @@ Output
 1.6666666666666667
 ```
 
-{% note info Integer Arithmetic %}Since JavaScript doesn't differentiate integers and floats, LiquidJS is not capable of integer arithmetic and the return type is always `number`, the string representation of which depends on its value.{% endnote %}
+In JavaScript, float and integer shares the same type `number` and we cannot tell the difference. For example:
+
+```javascript
+// always true
+5.0 === 5
+```
+
+You'll need to pass another `integerArithmetic` argument to enforce integer divide:
+
+Input
+```liquid
+{{ 5 | divided_by: 3, true }}
+```
+
+Output
+```text
+1
+```
 
 [floor]: ./floor.html
diff --git a/docs/source/zh-cn/filters/divided_by.md b/docs/source/zh-cn/filters/divided_by.md
index aedc2a20a..2eb2d4264 100644
--- a/docs/source/zh-cn/filters/divided_by.md
+++ b/docs/source/zh-cn/filters/divided_by.md
@@ -26,6 +26,23 @@ title: divided_by
 1.6666666666666667
 ```
 
-{% note info Integer Arithmetic %}Since JavaScript doesn't differentiate integers and floats, LiquidJS is not capable of integer arithmetic and the return type is always `number`, the string representation of which depends on its value.{% endnote %}
+在 JavaScript 里数字没有浮点和整数的区分，它们的类型都是 `number`：
+
+```javascript
+// always true
+5.0 === 5
+```
+
+因此如果需要做整数运算，需要传入额外的 `integerArithmetic` 参数：
+
+Input
+```liquid
+{{ 5 | divided_by: 3, true }}
+```
+
+Output
+```text
+1
+```
 
 [floor]: ./floor.html
diff --git a/src/builtin/filters/math.ts b/src/builtin/filters/math.ts
index 350fc1735..28be0cf82 100644
--- a/src/builtin/filters/math.ts
+++ b/src/builtin/filters/math.ts
@@ -4,7 +4,7 @@ export const abs = argumentsToValue(Math.abs)
 export const atLeast = argumentsToValue(Math.max)
 export const atMost = argumentsToValue(Math.min)
 export const ceil = argumentsToValue(Math.ceil)
-export const dividedBy = argumentsToValue((v: number, arg: number) => v / arg)
+export const dividedBy = argumentsToValue((dividend: number, divisor: number, integerArithmetic = false) => integerArithmetic ? Math.floor(dividend / divisor) : dividend / divisor)
 export const floor = argumentsToValue(Math.floor)
 export const minus = argumentsToValue((v: number, arg: number) => v - arg)
 export const modulo = argumentsToValue((v: number, arg: number) => v % arg)
diff --git a/test/e2e/issues.ts b/test/e2e/issues.ts
index c56941947..d1e058724 100644
--- a/test/e2e/issues.ts
+++ b/test/e2e/issues.ts
@@ -199,6 +199,11 @@ describe('Issues', function () {
     const html = engine.parseAndRenderSync('{{foo | size}}-{{bar.coo}}', { foo: 'foo', bar: Object.create({ coo: 'COO' }) })
     expect(html).to.equal('3-')
   })
+  it('#465 Liquidjs divided_by not compatible with Ruby/Shopify Liquid', () => {
+    const engine = new Liquid({ ownPropertyOnly: true })
+    const html = engine.parseAndRenderSync('{{ 5 | divided_by: 3, true }}')
+    expect(html).to.equal('1')
+  })
   it('#479 url_encode throws on undefined value', async () => {
     const engine = new Liquid({
       strictVariables: false
diff --git a/test/integration/builtin/filters/math.ts b/test/integration/builtin/filters/math.ts
index 1d1247a48..0220609ea 100644
--- a/test/integration/builtin/filters/math.ts
+++ b/test/integration/builtin/filters/math.ts
@@ -25,6 +25,8 @@ describe('filters/math', function () {
     it('should return 2 for 4,2', () => test('{{4 | divided_by: 2}}', '2'))
     it('should return 4 for 16,4', () => test('{{16 | divided_by: 4}}', '4'))
     it('should return 1 for 5,3', () => test('{{5 | divided_by: 3}}', (5 / 3).toString()))
+    it('should support integer arithmetic', () => test('{{5 | divided_by: 3, true}}', '1'))
+    it('should floor the result in integer arithmetic', () => test('{{ -5 | divided_by: 3, true}}', '-2'))
     it('should convert string to number', () => test('{{"6" | divided_by: "3"}}', '2'))
   })
   describe('floor', function () {