use isTruthy for and/or operators, fixes #47

src/operators.js

@@ -1,4 +1,5 @@
-var operators = {
+module.exports = function (isTruthy) {
+  return {
     '==': (l, r) => l === r,
     '!=': (l, r) => l !== r,
     '>': (l, r) => l !== null && r !== null && l > r,
@@ -10,8 +11,7 @@ var operators = {
       if (typeof l.indexOf !== 'function') return false
       return l.indexOf(r) > -1
     },
-  'and': (l, r) => l && r,
+    'and': (l, r) => isTruthy(l) && isTruthy(r),
-  'or': (l, r) => l || r
+    'or': (l, r) => isTruthy(l) || isTruthy(r)
+  }
 }
-
-module.exports = operators

src/syntax.js

@@ -1,4 +1,4 @@
-const operators = require('./operators.js')
+const operators = require('./operators.js')(isTruthy)
 const lexical = require('./lexical.js')
 const assert = require('../src/util/assert.js')
 

test/liquid.js

@@ -70,13 +70,9 @@ describe('liquid', function () {
   it('should render template multiple times', function () {
     var template = engine.parse('{{obj}}')
     return engine.render(template, ctx)
-      .then((result) => {
+      .then(result => expect(result).to.equal('{"foo":"bar"}'))
-        expect(result).to.equal('{"foo":"bar"}')
+      .then(() => engine.render(template, ctx))
-        return engine.render(template, ctx)
+      .then((result) => expect(result).to.equal('{"foo":"bar"}'))
-      })
-      .then((result) => {
-        return expect(result).to.equal('{"foo":"bar"}')
-      })
   })
   it('should render filters', function () {
     var template = engine.parse('<p>{{arr | join: "_"}}</p>')

test/syntax.js

@@ -14,6 +14,7 @@ describe('expression', function () {
     scope = Scope.factory({
       one: 1,
       two: 2,
+      empty: '',
       x: 'XXX',
       y: undefined,
       z: null
@@ -73,11 +74,20 @@ describe('expression', function () {
       expect(evalExp('"<=" == "<="', scope)).to.equal(true)
     })
 
-    it('should eval complex expression', function () {
+    describe('complex expression', function () {
-      expect(evalExp('1<2 and x contains "x"', scope)).to.equal(false)
+      it('should support value or value', function () {
-      expect(evalExp('1<2 or x contains "x"', scope)).to.equal(true)
         expect(evalExp('false or true', scope)).to.equal(true)
       })
+      it('should support < and contains', function () {
+        expect(evalExp('1<2 and x contains "x"', scope)).to.equal(false)
+      })
+      it('should support < or contains', function () {
+        expect(evalExp('1<2 or x contains "x"', scope)).to.equal(true)
+      })
+      it('should support value and !=', function () {
+        expect(evalExp('empty and empty != ""', scope)).to.equal(false)
+      })
+    })
 
     it('should eval range expression', function () {
       expect(evalExp('(2..4)', scope)).to.deep.equal([2, 3, 4])

test/tags/if.js

@@ -17,11 +17,30 @@ describe('tags/if', function () {
     return expect(liquid.parseAndRender(src, ctx))
       .to.be.rejectedWith(/tag {% if false%} not closed/)
   })
+  it('should support nested', function () {
+    var src = '{%if false%}{%if true%}{%else%}a{%endif%}{%endif%}'
+    return expect(liquid.parseAndRender(src, ctx))
+      .to.eventually.equal('')
+  })
+
+  describe('single value as condition', function () {
+    it('should support boolean', function () {
+      var src = '{% if false %}1{%elsif true%}2{%else%}3{%endif%}'
+      return expect(liquid.parseAndRender(src, ctx))
+        .to.eventually.equal('2')
+    })
     it('should treat Array truthy', function () {
       var src = '{%if emptyArray%}a{%endif%}'
       return expect(liquid.parseAndRender(src, ctx))
         .to.eventually.equal('a')
     })
+    it('should return true if empty string', function () {
+      var src = '{%if emptyString%}a{%endif%}'
+      return expect(liquid.parseAndRender(src, ctx))
+        .to.eventually.equal('a')
+    })
+  })
+  describe('expression as condition', function () {
     it('should support ==', function () {
       var src = '{% if 2==3 %}yes{%else%}no{%endif%}'
       return expect(liquid.parseAndRender(src, ctx))
@@ -37,67 +56,60 @@ describe('tags/if', function () {
       return expect(liquid.parseAndRender(src, ctx))
         .to.eventually.equal('yes')
     })
-  it('should support boolean', function () {
+    it('should support value and expression', function () {
-    var src = '{% if false %}1{%elsif true%}2{%else%}3{%endif%}'
+      var src = `X{%if version and version != '' %}x{{version}}y{%endif%}Y`
+      var ctx = { 'version': '' }
       return expect(liquid.parseAndRender(src, ctx))
-      .to.eventually.equal('2')
+        .to.eventually.equal('XY')
     })
-  it('should support nested', function () {
-    var src = '{%if false%}{%if true%}{%else%}a{%endif%}{%endif%}'
-    return expect(liquid.parseAndRender(src, ctx))
-      .to.eventually.equal('')
   })
-  it('should return true if empty string', function () {
+  describe('comparasion to null', function () {
-    var src = '{%if emptyString%}a{%endif%}'
+    it('should evaluate false for null < 10', function () {
-    return expect(liquid.parseAndRender(src, ctx))
-      .to.eventually.equal('a')
-  })
-
-  it('should return else when comparison on null 1', function () {
       var src = '{% if null < 10 %}yes{% else %}no{% endif %}'
       return expect(liquid.parseAndRender(src, ctx))
         .to.eventually.equal('no')
     })
 
-  it('should return else when comparison on null 2', function () {
+    it('should evaluate false for null > 10', function () {
-    var src = '{% if null <= 10 %}yes{% else %}no{% endif %}'
-    return expect(liquid.parseAndRender(src, ctx))
-      .to.eventually.equal('no')
-  })
-
-  it('should return else when comparison on null 3', function () {
-    var src = '{% if null >= 10 %}yes{% else %}no{% endif %}'
-    return expect(liquid.parseAndRender(src, ctx))
-      .to.eventually.equal('no')
-  })
-
-  it('should return else when comparison on null 4', function () {
       var src = '{% if null > 10 %}yes{% else %}no{% endif %}'
       return expect(liquid.parseAndRender(src, ctx))
         .to.eventually.equal('no')
     })
 
-  it('should return else when comparison on null 5', function () {
+    it('should evaluate false for null <= 10', function () {
+      var src = '{% if null <= 10 %}yes{% else %}no{% endif %}'
+      return expect(liquid.parseAndRender(src, ctx))
+        .to.eventually.equal('no')
+    })
+
+    it('should evaluate false for null >= 10', function () {
+      var src = '{% if null >= 10 %}yes{% else %}no{% endif %}'
+      return expect(liquid.parseAndRender(src, ctx))
+        .to.eventually.equal('no')
+    })
+
+    it('should evaluate false for 10 < null', function () {
       var src = '{% if 10 < null %}yes{% else %}no{% endif %}'
       return expect(liquid.parseAndRender(src, ctx))
         .to.eventually.equal('no')
     })
 
-  it('should return else when comparison on null 6', function () {
+    it('should evaluate false for 10 > null', function () {
+      var src = '{% if 10 > null %}yes{% else %}no{% endif %}'
+      return expect(liquid.parseAndRender(src, ctx))
+        .to.eventually.equal('no')
+    })
+
+    it('should evaluate false for 10 <= null', function () {
       var src = '{% if 10 <= null %}yes{% else %}no{% endif %}'
       return expect(liquid.parseAndRender(src, ctx))
         .to.eventually.equal('no')
     })
 
-  it('should return else when comparison on null 7', function () {
+    it('should evaluate false for 10 >= null', function () {
       var src = '{% if 10 >= null %}yes{% else %}no{% endif %}'
       return expect(liquid.parseAndRender(src, ctx))
         .to.eventually.equal('no')
     })
-
-  it('should return else when comparison on null 8', function () {
-    var src = '{% if 10 > null %}yes{% else %}no{% endif %}'
-    return expect(liquid.parseAndRender(src, ctx))
-      .to.eventually.equal('no')
   })
 })