From 3fa369c1cd2b0d6d0a7964638fb35ace5010e8b8 Mon Sep 17 00:00:00 2001
From: komed3 <pk97@outlook.de>
Date: Wed, 27 Dec 2023 11:21:22 +0100
Subject: [PATCH] add threshold to specify the minimum required similarity

---
 README.md | 18 +++++++++++-------
 index.js  | 33 ++++++++++++++++++++-------------
 2 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/README.md b/README.md
index 7c2acc5..5615637 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ This lightweight npm package can be used to __calculate the similarity of string
 
 ## Install
 
-Using Node.js install the package using shell command:
+Using __Node.js__, install the package with the following shell command:
 
 ```sh
 npm install cmpstr
@@ -63,7 +63,7 @@ let matches = cmpstr.levenshteinMatch( 'best', [
 Using JavaScript load this package by embed this file via [jsDelivr](https://www.jsdelivr.com/package/npm/cmpstr):
 
 ```js
-import cmpstr from "https://cdn.jsdelivr.net/npm/cmpstr@1.0.2/+esm";
+import cmpstr from "https://cdn.jsdelivr.net/npm/cmpstr@1.0.3/+esm";
 ```
 
 Remember: To use ``import`` you need to load your JavaScript file as ``type="module"``.
@@ -91,9 +91,9 @@ Returns the match percentage of two strings ``a`` and ``b``. The output value is
 
 Returns the best match of the string ``str`` against the array ``arr`` of passed strings. The function returns the most closely matched string found in the array.
 
-#### ``levenshteinMatch( str, arr [, flags = null ] )``
+#### ``levenshteinMatch( str, arr [, flags = null [, threshold = 0 ] ] )``
 
-Calculates the similarity of all strings contained in the array ``arr`` according to Levenshtein compared to ``str`` and returns an array of all samples sorted by matching in descending order.
+Calculates the similarity of all strings contained in the array ``arr`` according to Levenshtein compared to ``str`` and returns an array of all samples sorted by matching in descending order. The ``threshold`` specifies the minimum required similarity.
 
 ### Sørensen-Dice coefficient
 
@@ -105,9 +105,9 @@ This function evaluates the similarity of two given strings ``a`` and ``b`` as p
 
 As another way to find the best match between the string ``str`` and a given array ``arr`` of samples, this function uses the Sørensen-Dice coefficient. It returns the most matching string as well.
 
-#### ``diceMatch( str, arr [, flags = null ] )``
+#### ``diceMatch( str, arr [, flags = null [, threshold = 0 ] ] )``
 
-Calculates the similarity of all strings contained in the array ``arr`` according to Sørensen-Dice coefficient compared to ``str`` and returns an array of all samples sorted by matching in descending order.
+Calculates the similarity of all strings contained in the array ``arr`` according to Sørensen-Dice coefficient compared to ``str`` and returns an array of all samples sorted by matching in descending order. The ``threshold`` specifies the minimum required similarity.
 
 ### Flags
 
@@ -120,6 +120,10 @@ Each method can be passed the ``flags`` options listed below:
 
 ## Patch notes
 
+### 1.0.3
+
+* Add ``threshold`` to specify the minimum required similarity
+
 ### 1.0.2
 
 * Add normalize options ``i`` and ``s``
@@ -131,4 +135,4 @@ Each method can be passed the ``flags`` options listed below:
 
 ### 1.0.0
 
-* Initial release
+* Initial release
\ No newline at end of file
diff --git a/index.js b/index.js
index 5f912f0..b5a4169 100644
--- a/index.js
+++ b/index.js
@@ -3,11 +3,11 @@
  * lightweight npm package to calculate string similarity
  * 
  * @author komed3 (Paul Köhler)
- * @version 1.0.2
+ * @version 1.0.3
  * @license MIT
  */
 
-'use strict'
+'use strict';
 
 /**
  * basic functions
@@ -83,7 +83,7 @@ const str2bigrams = ( str ) => {
  * @param {Null|String} flags options
  * @returns similarity
  */
-const cpmByAlgo = ( algo, a, b, flags ) => {
+const cpmByAlgo = ( algo, a, b, flags = null ) => {
 
     switch( algo ) {
 
@@ -108,7 +108,7 @@ const cpmByAlgo = ( algo, a, b, flags ) => {
  * @param {Null|String} flags options
  * @returns closest target
  */
-const findClosest = ( algo, test, arr, flags ) => {
+const findClosest = ( algo, test, arr, flags = null ) => {
 
     let best = -Infinity,
         idx = 0,
@@ -143,9 +143,10 @@ const findClosest = ( algo, test, arr, flags ) => {
  * @param {String} test test string
  * @param {Array} arr targets to test
  * @param {Null|String} flags options
+ * @param {Float} threshold required similarity
  * @returns sorted matches
  */
-const bestMatch = ( algo, test, arr, flags = null ) => {
+const bestMatch = ( algo, test, arr, flags = null, threshold = 0 ) => {
 
     let matches = [],
         pct;
@@ -156,10 +157,14 @@ const bestMatch = ( algo, test, arr, flags = null ) => {
 
         pct = cpmByAlgo( algo, test, str, flags );
 
-        matches.push( {
-            target: str,
-            match: pct
-        } );
+        if( pct >= threshold ) {
+
+            matches.push( {
+                target: str,
+                match: pct
+            } );
+
+        }
 
     } );
 
@@ -329,11 +334,12 @@ const levenshteinClosest = ( test, arr, flags = null ) => {
  * @param {String} test test string
  * @param {Array} arr targets to test
  * @param {Null|String} flags options
+ * @param {Float} threshold required similarity
  * @returns sorted matches
  */
-const levenshteinMatch = ( test, arr, flags = null ) => {
+const levenshteinMatch = ( test, arr, flags = null, threshold = 0 ) => {
 
-    return bestMatch( 'levenshtein', test, arr, flags );
+    return bestMatch( 'levenshtein', test, arr, flags, threshold );
 
 };
 
@@ -403,11 +409,12 @@ const diceClosest = ( test, arr, flags = null ) => {
  * @param {String} test test string
  * @param {Array} arr targets to test
  * @param {Null|String} flags options
+ * @param {Float} threshold required similarity
  * @returns sorted matches
  */
-const diceMatch = ( test, arr, flags = null ) => {
+const diceMatch = ( test, arr, flags = null, threshold = 0 ) => {
 
-    return bestMatch( 'diceCoefficient', test, arr, flags );
+    return bestMatch( 'diceCoefficient', test, arr, flags, threshold );
 
 };