Fix bug when "constructor" is a term

src/MiniSearch.js

@@ -710,14 +710,18 @@ const termResults = function (self, term, boosts, boostDocument, indexData, weig
       const normalizedLength = self._fieldLength[documentId][fieldId] / self._averageFieldLength[fieldId]
       results[documentId] = results[documentId] || { score: 0, match: {}, terms: [] }
       results[documentId].terms.push(term)
-      results[documentId].match[term] = results[documentId].match[term] || []
+      results[documentId].match[term] = getOwnProperty(results[documentId].match, term) || []
       results[documentId].score += docBoost * score(tf, df, self._documentCount, normalizedLength, boost, editDistance)
       results[documentId].match[term].push(field)
     })
     return results
   }, {})
 }
 
+const getOwnProperty = function (object, property) {
+  return Object.prototype.hasOwnProperty.call(object, property) ? object[property] : undefined
+}
+
 const addFieldLength = function (self, documentId, fieldId, count, length) {
   self._averageFieldLength[fieldId] = self._averageFieldLength[fieldId] || 0
   const totalLength = (self._averageFieldLength[fieldId] * count) + length

src/MiniSearch.test.js

@@ -583,6 +583,22 @@ describe('MiniSearch', () => {
           expect(processTerm).toHaveBeenCalledWith(term)
         })
       })
+
+      it('does not break when special properties of object are used as a term', () => {
+        const specialWords = ['constructor', 'hasOwnProperty', 'isPrototypeOf']
+        const ms = new MiniSearch({ fields: ['text'] })
+        const processTerm = MiniSearch.getDefault('processTerm')
+
+        ms.add({ id: 1, text: specialWords.join(' ') })
+
+        specialWords.forEach((word) => {
+          expect(() => { ms.search(word) }).not.toThrowError()
+
+          const results = ms.search(word)
+          expect(results[0].id).toEqual(1)
+          expect(results[0].match[processTerm(word)]).toEqual(['text'])
+        })
+      })
     })
   })