feat: add fuzzy matching algorithm for tab completions

Signed-off-by: Snehil Shah <[email protected]>

Author: Snehil-Shah

lib/node_modules/@stdlib/repl/lib/filter_by_prefix.js

@@ -21,6 +21,73 @@
 // MODULES //
 
 var startsWith = require( '@stdlib/string/starts-with' );
+var max = require( '@stdlib/math/base/special/max' );
+var abs = require( '@stdlib/math/base/special/abs' );
+
+
+// FUNCTIONS //
+
+/**
+* Checks if the completion is a fuzzy match for the input.
+*
+* A fuzzy match is determined by the number and order of matching characters, penalizing large distances between matches.
+* A score above or equal to 0.8 indicates a match.
+*
+* @private
+* @param {string} completion - The completion string.
+* @param {string} input - The input string.
+* @returns {boolean} - True if the completion is a fuzzy match for the input, false otherwise.
+*/
+function fuzzyMatch( completion, input ) {
+	var charPositions;
+	var finalScore;
+	var positions;
+	var distance;
+	var score;
+	var index;
+	var char;
+	var i;
+	var j;
+
+	if ( startsWith( completion, input ) ) {
+		return true; // Return true for perfect matches
+	}
+
+	// Preprocess the completion string to get the positions of each character
+	positions = {};
+	for ( i = 0; i < completion.length; i++ ) {
+		char = completion[ i ];
+		if (!positions[ char ]) {
+			positions[ char] = [];
+		}
+		positions[ char ].push( i );
+	}
+
+	score = 0;
+	index = 0;
+	for ( i = 0; i < input.length; i++ ) {
+		charPositions = positions[ input[ i ] ];
+		if ( !charPositions ) {
+			continue;
+		}
+
+		// Find the next position of the character that is greater than or equal to index
+		j = 0;
+		while ( j < charPositions.length && charPositions[ j ] < index ) {
+			j += 1;
+		}
+		if ( j === charPositions.length ) {
+			continue;
+		}
+
+		distance = abs( charPositions[ j ] - i );
+		score += max( 0, 1 - ( distance * 0.25 ) ); // Subtract a penalty based on the distance between matching characters
+		index = charPositions[ j ] + 1;
+	}
+	finalScore = score / input.length; // Calculate relative score
+
+	return finalScore >= 0.65;
+}
 
 
 // MAIN //
@@ -37,7 +104,7 @@ var startsWith = require( '@stdlib/string/starts-with' );
 function filterByPrefix( out, arr, str ) {
 	var i;
 	for ( i = 0; i < arr.length; i++ ) {
-		if ( startsWith( arr[ i ], str ) ) {
+		if ( fuzzyMatch( arr[ i ], str ) ) {
 			out.push( arr[ i ] );
 		}
 	}