fix: contains operator does not support Drop, fixes #492

test/e2e/issues.ts

@@ -1,4 +1,4 @@
-import { Liquid } from '../..'
+import { Liquid, Drop } from '../..'
 import { expect, use } from 'chai'
 import * as chaiAsPromised from 'chai-as-promised'
 import * as sinon from 'sinon'
@@ -232,4 +232,13 @@ describe('Issues', function () {
     const html = await engine.parseAndRender(`{% assign a = "x,y,z" | split: ',' -%}{{ a[-1] }} {{ a[-3] }} {{ a[-8] }}`)
     expect(html).to.equal('z x ')
   })
+  it('#492 contains operator does not support Drop', async () => {
+    class TemplateDrop extends Drop {
+      valueOf () { return 'product' }
+    }
+    const engine = new Liquid()
+    const ctx = { template: new TemplateDrop() }
+    const html = await engine.parseAndRender(`{% if template contains "product" %}contains{%endif%}`, ctx)
+    expect(html).to.equal('contains')
+  })
 })

test/unit/render/expression.ts

@@ -1,5 +1,6 @@
 import { Tokenizer } from '../../../src/parser/tokenizer'
 import { expect } from 'chai'
+import { Drop } from '../../../src/drop/drop'
 import { Context } from '../../../src/context/context'
 import { toThenable } from '../../../src/util/async'
 import { defaultOperators } from '../../../src/render/operator'
@@ -130,6 +131,13 @@ describe('Expression', function () {
     it('should support < or contains', async function () {
       expect(await toThenable(create('1 < 2 or x contains "x"').evaluate(ctx, false))).to.equal(true)
     })
+    it('should support Drops for "x contains "x""', async () => {
+      class TemplateDrop extends Drop {
+        valueOf () { return 'X' }
+      }
+      const ctx = new Context({ x: 'XXX', X: new TemplateDrop() })
+      expect(await toThenable(create('x contains X').evaluate(ctx, false))).to.equal(true)
+    })
     it('should support value and !=', async function () {
       const ctx = new Context({ empty: '' })
       expect(await toThenable(create('empty and empty != ""').evaluate(ctx, false))).to.equal(false)