feat: support not operator, #575

test/e2e/issues.ts

@@ -377,4 +377,16 @@ describe('Issues', function () {
     const html = await liquid.parseAndRender(tpl)
     expect(html).to.match(/\w+, January \d+, 2023 at \d+:\d\d [ap]m [-+]\d\d\d\d/)
   })
+  it('#575 Add support for Not operator', async () => {
+    const liquid = new Liquid()
+    const tpl = `
+    {% if link and not button %}
+      <a href="{{ link }}">Lot more code here</a>
+    {% else %}
+      <div>Lot more code here</div>
+    {% endif %}`
+    const ctx = { link: 'https://example.com', button: false }
+    const html = await liquid.parseAndRender(tpl, ctx)
+    expect(html.trim()).to.equal('<a href="https://example.com">Lot more code here</a>')
+  })
 })

test/unit/parser/tokenizer.ts

@@ -397,9 +397,11 @@ describe('Tokenizer', function () {
     it('should read expression `a ==`', () => {
       const exp = [...new Tokenizer('a ==').readExpressionTokens()]
 
-      expect(exp).to.have.lengthOf(1)
+      expect(exp).to.have.lengthOf(2)
       expect(exp[0]).to.be.instanceOf(PropertyAccessToken)
       expect(exp[0].getText()).to.deep.equal('a')
+      expect(exp[1]).to.be.instanceOf(OperatorToken)
+      expect(exp[1].getText()).to.deep.equal('==')
     })
     it('should read expression `a==b`', () => {
       const exp = new Tokenizer('a==b').readExpressionTokens()

test/unit/render/expression.ts

@@ -154,6 +154,13 @@ describe('Expression', function () {
       const ctx = new Context({ obj: { foo: 'FOO' }, keys: { "what's this": 'foo' } })
       expect(await toPromise(create('obj[keys["what\'s this"]]').evaluate(ctx, false))).to.equal('FOO')
     })
+    it('should support not', async function () {
+      expect(await toPromise(create('not 1 < 2').evaluate(ctx))).to.equal(false)
+    })
+    it('not should have higher precedence than and/or', async function () {
+      expect(await toPromise(create('not 1 < 2 or not 1 > 2').evaluate(ctx))).to.equal(true)
+      expect(await toPromise(create('not 1 < 2 and not 1 > 2').evaluate(ctx))).to.equal(false)
+    })
   })
 
   describe('sync', function () {