Allow fact values to be undefined

Author: Cache Hamm

src/fact.js

@@ -26,9 +26,9 @@ class Fact {
     }
 
     if (!this.id) throw new Error('factId required')
-    if (typeof this.value === 'undefined' && typeof this.calculationMethod === 'undefined') {
-      throw new Error('facts must have a value or method')
-    }
+    // if (typeof this.value === 'undefined' && typeof this.calculationMethod === 'undefined') {
+    //   throw new Error('facts must have a value or method')
+    // }
 
     this.priority = parseInt(options.priority || 1, 10)
     this.options = Object.assign({}, defaultOptions, options)

test/fact.test.js

@@ -29,10 +29,6 @@ describe('Fact', () => {
       it('throws if no id provided', () => {
         expect(subject).to.throw(/factId required/)
       })
-
-      it('throws if no definition provided', () => {
-        expect(subject.bind(null, 'factId')).to.throw(/facts must have a value or method/)
-      })
     })
   })