fix(search): deduplicate and merge overlapping match indices

When a search pattern exceeds MAX_BITS (32 chars), it is split into
chunks. Each chunk produces its own match indices, which were
concatenated without deduplication, resulting in duplicate and
overlapping index ranges. This broke highlighting implementations.

Now indices from multiple chunks are sorted and merged into
non-overlapping ranges before being returned.

Closes #735

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: krisk

dist/fuse.basic.cjs

@@ -800,6 +800,23 @@ var stripDiacritics = String.prototype.normalize ? function (str) {
   return str;
 };
 
+function mergeIndices(indices) {
+  if (indices.length <= 1) return indices;
+  indices.sort(function (a, b) {
+    return a[0] - b[0] || a[1] - b[1];
+  });
+  var merged = [indices[0]];
+  for (var i = 1, len = indices.length; i < len; i += 1) {
+    var last = merged[merged.length - 1];
+    var curr = indices[i];
+    if (curr[0] <= last[1] + 1) {
+      last[1] = Math.max(last[1], curr[1]);
+    } else {
+      merged.push(curr);
+    }
+  }
+  return merged;
+}
 var BitapSearch = /*#__PURE__*/function () {
   function BitapSearch(pattern) {
     var _this = this;
@@ -927,7 +944,7 @@ var BitapSearch = /*#__PURE__*/function () {
         score: hasMatches ? totalScore / this.chunks.length : 1
       };
       if (hasMatches && includeMatches) {
-        result.indices = allIndices;
+        result.indices = mergeIndices(allIndices);
       }
       return result;
     }

dist/fuse.basic.js

@@ -804,6 +804,23 @@
     return str;
   };
 
+  function mergeIndices(indices) {
+    if (indices.length <= 1) return indices;
+    indices.sort(function (a, b) {
+      return a[0] - b[0] || a[1] - b[1];
+    });
+    var merged = [indices[0]];
+    for (var i = 1, len = indices.length; i < len; i += 1) {
+      var last = merged[merged.length - 1];
+      var curr = indices[i];
+      if (curr[0] <= last[1] + 1) {
+        last[1] = Math.max(last[1], curr[1]);
+      } else {
+        merged.push(curr);
+      }
+    }
+    return merged;
+  }
   var BitapSearch = /*#__PURE__*/function () {
     function BitapSearch(pattern) {
       var _this = this;
@@ -931,7 +948,7 @@
           score: hasMatches ? totalScore / this.chunks.length : 1
         };
         if (hasMatches && includeMatches) {
-          result.indices = allIndices;
+          result.indices = mergeIndices(allIndices);
         }
         return result;
       }

dist/fuse.basic.min.cjs

@@ -715,6 +715,26 @@ const stripDiacritics = String.prototype.normalize
     ? ((str) => str.normalize('NFD').replace(/[\u0300-\u036F\u0483-\u0489\u0591-\u05BD\u05BF\u05C1\u05C2\u05C4\u05C5\u05C7\u0610-\u061A\u064B-\u065F\u0670\u06D6-\u06DC\u06DF-\u06E4\u06E7\u06E8\u06EA-\u06ED\u0711\u0730-\u074A\u07A6-\u07B0\u07EB-\u07F3\u07FD\u0816-\u0819\u081B-\u0823\u0825-\u0827\u0829-\u082D\u0859-\u085B\u08D3-\u08E1\u08E3-\u0903\u093A-\u093C\u093E-\u094F\u0951-\u0957\u0962\u0963\u0981-\u0983\u09BC\u09BE-\u09C4\u09C7\u09C8\u09CB-\u09CD\u09D7\u09E2\u09E3\u09FE\u0A01-\u0A03\u0A3C\u0A3E-\u0A42\u0A47\u0A48\u0A4B-\u0A4D\u0A51\u0A70\u0A71\u0A75\u0A81-\u0A83\u0ABC\u0ABE-\u0AC5\u0AC7-\u0AC9\u0ACB-\u0ACD\u0AE2\u0AE3\u0AFA-\u0AFF\u0B01-\u0B03\u0B3C\u0B3E-\u0B44\u0B47\u0B48\u0B4B-\u0B4D\u0B56\u0B57\u0B62\u0B63\u0B82\u0BBE-\u0BC2\u0BC6-\u0BC8\u0BCA-\u0BCD\u0BD7\u0C00-\u0C04\u0C3E-\u0C44\u0C46-\u0C48\u0C4A-\u0C4D\u0C55\u0C56\u0C62\u0C63\u0C81-\u0C83\u0CBC\u0CBE-\u0CC4\u0CC6-\u0CC8\u0CCA-\u0CCD\u0CD5\u0CD6\u0CE2\u0CE3\u0D00-\u0D03\u0D3B\u0D3C\u0D3E-\u0D44\u0D46-\u0D48\u0D4A-\u0D4D\u0D57\u0D62\u0D63\u0D82\u0D83\u0DCA\u0DCF-\u0DD4\u0DD6\u0DD8-\u0DDF\u0DF2\u0DF3\u0E31\u0E34-\u0E3A\u0E47-\u0E4E\u0EB1\u0EB4-\u0EB9\u0EBB\u0EBC\u0EC8-\u0ECD\u0F18\u0F19\u0F35\u0F37\u0F39\u0F3E\u0F3F\u0F71-\u0F84\u0F86\u0F87\u0F8D-\u0F97\u0F99-\u0FBC\u0FC6\u102B-\u103E\u1056-\u1059\u105E-\u1060\u1062-\u1064\u1067-\u106D\u1071-\u1074\u1082-\u108D\u108F\u109A-\u109D\u135D-\u135F\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17B4-\u17D3\u17DD\u180B-\u180D\u1885\u1886\u18A9\u1920-\u192B\u1930-\u193B\u1A17-\u1A1B\u1A55-\u1A5E\u1A60-\u1A7C\u1A7F\u1AB0-\u1ABE\u1B00-\u1B04\u1B34-\u1B44\u1B6B-\u1B73\u1B80-\u1B82\u1BA1-\u1BAD\u1BE6-\u1BF3\u1C24-\u1C37\u1CD0-\u1CD2\u1CD4-\u1CE8\u1CED\u1CF2-\u1CF4\u1CF7-\u1CF9\u1DC0-\u1DF9\u1DFB-\u1DFF\u20D0-\u20F0\u2CEF-\u2CF1\u2D7F\u2DE0-\u2DFF\u302A-\u302F\u3099\u309A\uA66F-\uA672\uA674-\uA67D\uA69E\uA69F\uA6F0\uA6F1\uA802\uA806\uA80B\uA823-\uA827\uA880\uA881\uA8B4-\uA8C5\uA8E0-\uA8F1\uA8FF\uA926-\uA92D\uA947-\uA953\uA980-\uA983\uA9B3-\uA9C0\uA9E5\uAA29-\uAA36\uAA43\uAA4C\uAA4D\uAA7B-\uAA7D\uAAB0\uAAB2-\uAAB4\uAAB7\uAAB8\uAABE\uAABF\uAAC1\uAAEB-\uAAEF\uAAF5\uAAF6\uABE3-\uABEA\uABEC\uABED\uFB1E\uFE00-\uFE0F\uFE20-\uFE2F]/g, ''))
     : ((str) => str);
 
+function mergeIndices(indices) {
+  if (indices.length <= 1) return indices
+
+  indices.sort((a, b) => a[0] - b[0] || a[1] - b[1]);
+
+  const merged = [indices[0]];
+
+  for (let i = 1, len = indices.length; i < len; i += 1) {
+    const last = merged[merged.length - 1];
+    const curr = indices[i];
+    if (curr[0] <= last[1] + 1) {
+      last[1] = Math.max(last[1], curr[1]);
+    } else {
+      merged.push(curr);
+    }
+  }
+
+  return merged
+}
+
 class BitapSearch {
   constructor(
     pattern,
@@ -843,7 +863,7 @@ class BitapSearch {
     };
 
     if (hasMatches && includeMatches) {
-      result.indices = allIndices;
+      result.indices = mergeIndices(allIndices);
     }
 
     return result

dist/fuse.basic.min.js

@@ -867,6 +867,23 @@ var stripDiacritics = String.prototype.normalize ? function (str) {
   return str;
 };
 
+function mergeIndices(indices) {
+  if (indices.length <= 1) return indices;
+  indices.sort(function (a, b) {
+    return a[0] - b[0] || a[1] - b[1];
+  });
+  var merged = [indices[0]];
+  for (var i = 1, len = indices.length; i < len; i += 1) {
+    var last = merged[merged.length - 1];
+    var curr = indices[i];
+    if (curr[0] <= last[1] + 1) {
+      last[1] = Math.max(last[1], curr[1]);
+    } else {
+      merged.push(curr);
+    }
+  }
+  return merged;
+}
 var BitapSearch = /*#__PURE__*/function () {
   function BitapSearch(pattern) {
     var _this = this;
@@ -994,7 +1011,7 @@ var BitapSearch = /*#__PURE__*/function () {
         score: hasMatches ? totalScore / this.chunks.length : 1
       };
       if (hasMatches && includeMatches) {
-        result.indices = allIndices;
+        result.indices = mergeIndices(allIndices);
       }
       return result;
     }

dist/fuse.basic.min.mjs

@@ -871,6 +871,23 @@
     return str;
   };
 
+  function mergeIndices(indices) {
+    if (indices.length <= 1) return indices;
+    indices.sort(function (a, b) {
+      return a[0] - b[0] || a[1] - b[1];
+    });
+    var merged = [indices[0]];
+    for (var i = 1, len = indices.length; i < len; i += 1) {
+      var last = merged[merged.length - 1];
+      var curr = indices[i];
+      if (curr[0] <= last[1] + 1) {
+        last[1] = Math.max(last[1], curr[1]);
+      } else {
+        merged.push(curr);
+      }
+    }
+    return merged;
+  }
   var BitapSearch = /*#__PURE__*/function () {
     function BitapSearch(pattern) {
       var _this = this;
@@ -998,7 +1015,7 @@
           score: hasMatches ? totalScore / this.chunks.length : 1
         };
         if (hasMatches && includeMatches) {
-          result.indices = allIndices;
+          result.indices = mergeIndices(allIndices);
         }
         return result;
       }