Added separate methods for Levenshtein with search (#594)

* Added separate methods for Levenshtein with search

* Added some spaces (coding standard)

lib/natural/distance/index.js

@@ -25,5 +25,7 @@ THE SOFTWARE.
 exports.JaroWinklerDistance = require('./jaro-winkler_distance')
 exports.LevenshteinDistance = require('./levenshtein_distance').LevenshteinDistance
 exports.DamerauLevenshteinDistance = require('./levenshtein_distance').DamerauLevenshteinDistance
+exports.LevenshteinDistanceSearch = require('./levenshtein_distance').LevenshteinDistanceSearch
+exports.DamerauLevenshteinDistanceSearch = require('./levenshtein_distance').DamerauLevenshteinDistanceSearch
 exports.DiceCoefficient = require('./dice_coefficient')
 exports.HammingDistance = require('./hamming_distance')

lib/natural/distance/levenshtein_distance.js

@@ -94,13 +94,27 @@ function DamerauLevenshteinDistance (source, target, options) {
   const damLevOptions = _.extend(
     { transposition_cost: 1, restricted: false },
     options || {},
-    { damerau: true }
+    { damerau: true, search: false }
   )
   return levenshteinDistance(source, target, damLevOptions)
 }
 
+function DamerauLevenshteinDistanceSearch (source, target, options) {
+  const damLevOptions = _.extend(
+    { transposition_cost: 1, restricted: false },
+    options || {},
+    { damerau: true, search: true }
+  )
+  return levenshteinDistance(source, target, damLevOptions)
+}
+
+function LevenshteinDistanceSearch (source, target, options) {
+  const levOptions = _.extend({}, options || {}, { damerau: false, search: true })
+  return levenshteinDistance(source, target, levOptions)
+}
+
 function LevenshteinDistance (source, target, options) {
-  const levOptions = _.extend({}, options || {}, { damerau: false })
+  const levOptions = _.extend({}, options || {}, { damerau: false, search: false })
   return levenshteinDistance(source, target, levOptions)
 }
 
@@ -221,5 +235,7 @@ function levenshteinDistance (source, target, options) {
 
 module.exports = {
   LevenshteinDistance: LevenshteinDistance,
-  DamerauLevenshteinDistance: DamerauLevenshteinDistance
+  LevenshteinDistanceSearch: LevenshteinDistanceSearch,
+  DamerauLevenshteinDistance: DamerauLevenshteinDistance,
+  DamerauLevenshteinDistanceSearch: DamerauLevenshteinDistanceSearch
 }

spec/levenshtein_spec.js

@@ -24,38 +24,40 @@ THE SOFTWARE.
 
 const levenshteinDistance =
   require('../lib/natural/distance/levenshtein_distance').LevenshteinDistance
+const levenshteinDistanceSearch =
+  require('../lib/natural/distance/levenshtein_distance').LevenshteinDistanceSearch
 
 describe('levenshtein_distance', function () {
   describe('options.search = true', function () {
     it('should find cheapest substring', function () {
-      expect(levenshteinDistance('kitten', 'sitting', { search: true }))
+      expect(levenshteinDistanceSearch('kitten', 'sitting'))
         .toEqual({ substring: 'sittin', distance: 2, offset: 0 })
     })
 
     it('should find 0 cost substring in target', function () {
-      expect(levenshteinDistance('doctor', 'the doctor is in', { search: true }))
+      expect(levenshteinDistanceSearch('doctor', 'the doctor is in'))
         .toEqual({ substring: 'doctor', distance: 0, offset: 4 })
     })
 
     it('should find 1 cost substring in target', function () {
-      expect(levenshteinDistance('doctor', 'the doktor is in', { search: true }))
+      expect(levenshteinDistanceSearch('doctor', 'the doktor is in'))
         .toEqual({ substring: 'doktor', distance: 1, offset: 4 })
     })
 
     it('should return empty substring when that is cleapest match', function () {
-      expect(levenshteinDistance('doctor', '000000000000', { search: true }))
+      expect(levenshteinDistanceSearch('doctor', '000000000000'))
         .toEqual({ substring: '', distance: 6, offset: 0 })
     })
 
     it('different insertion costs should work', function () {
       // delete 10 0's at cost 1 and insert the letters for doctor at cost -1
-      expect(levenshteinDistance('0000000000', 'doctor', { search: true, insertion_cost: -1 }))
+      expect(levenshteinDistanceSearch('0000000000', 'doctor', { insertion_cost: -1 }))
         .toEqual({ substring: 'doctor', distance: 4, offset: 0 })
     })
 
     it('different deletion costs should work', function () {
       // delete 10 0's at cost -10
-      expect(levenshteinDistance('0000000000', 'doctor', { search: true, deletion_cost: -1 }))
+      expect(levenshteinDistanceSearch('0000000000', 'doctor', { deletion_cost: -1 }))
         .toEqual({ substring: '', distance: -10, offset: 0 })
     })
   })