refactor: change separate tools by category

core/stdlib/src/text/levenshtein-distance/index.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from 'vitest';
+import {levenshteinDistance} from '.';
+  
+describe('levenshteinDistance', () => {
+    it('calculate edit distance between two strings', () => {  
+      // just one substitution I at the beginning
+      expect(levenshteinDistance('islander', 'slander')).toBe(1);
+  
+      // substitution M->K, T->M and add an A to the end
+      expect(levenshteinDistance('mart', 'karma')).toBe(3);
+  
+      // substitution K->S, E->I and insert G at the end
+      expect(levenshteinDistance('kitten', 'sitting')).toBe(3);
+  
+      // should add 4 letters FOOT at the beginning
+      expect(levenshteinDistance('ball', 'football')).toBe(4);
+  
+      // should delete 4 letters FOOT at the beginning
+      expect(levenshteinDistance('football', 'foot')).toBe(4);
+  
+      // needs to substitute the first 5 chars INTEN->EXECU
+      expect(levenshteinDistance('intention', 'execution')).toBe(5);
+    });
+
+    it('handle empty strings', () => {
+      expect(levenshteinDistance('', '')).toBe(0);
+      expect(levenshteinDistance('a', '')).toBe(1);
+      expect(levenshteinDistance('', 'a')).toBe(1);
+      expect(levenshteinDistance('abc', '')).toBe(3);
+      expect(levenshteinDistance('', 'abc')).toBe(3);
+    });
+  });

core/stdlib/src/text/levenshtein-distance/index.ts

@@ -0,0 +1,46 @@
+/**
+ * @name levenshteinDistance
+ * @category Text
+ * @description Calculate the Levenshtein distance between two strings
+ * 
+ * @param {string} left First string
+ * @param {string} right Second string
+ * @returns {number} The Levenshtein distance between the two strings
+ *
+ * @since 0.0.1
+ */
+export function levenshteinDistance(left: string, right: string): number {
+    if (left === right) return 0;
+
+    if (left.length === 0) return right.length;
+    if (right.length === 0) return left.length;
+
+    // Create empty edit distance matrix for all possible modifications of
+    // substrings of left to substrings of right
+    const distanceMatrix = Array(right.length + 1).fill(null).map(() => Array(left.length + 1).fill(null));
+
+    // Fill the first row of the matrix
+    // If this is the first row, we're transforming from an empty string to left
+    // In this case, the number of operations equals the length of left substring
+    for (let i = 0; i <= left.length; i++)
+        distanceMatrix[0]![i]! = i;
+
+    // Fill the first column of the matrix
+    // If this is the first column, we're transforming empty string to right
+    // In this case, the number of operations equals the length of right substring
+    for (let j = 0; j <= right.length; j++)
+        distanceMatrix[j]![0]! = j;
+
+    for (let j = 1; j <= right.length; j++) {
+        for (let i = 1; i <= left.length; i++) {
+            const indicator = left[i - 1] === right[j - 1] ? 0 : 1;
+            distanceMatrix[j]![i]! = Math.min(
+                distanceMatrix[j]![i - 1]! + 1, // deletion
+                distanceMatrix[j - 1]![i]! + 1, // insertion
+                distanceMatrix[j - 1]![i - 1]! + indicator // substitution
+            );
+        }
+    }
+
+    return distanceMatrix[right.length]![left.length]!;
+}