doc

doc/js/search_ranker.js

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+/**
+ * Aliki Search Implementation
+ *
+ * Search algorithm with the following priorities:
+ * 1. Exact full_name match always wins (for namespace/method queries)
+ * 2. Exact name match gets high priority
+ * 3. Match types:
+ *    - Namespace queries (::) and method queries (# or .) match against full_name
+ *    - Regular queries match against unqualified name
+ *    - Prefix (10000) > substring (5000) > fuzzy (1000)
+ * 4. First character determines type priority:
+ *    - Starts with lowercase: methods first
+ *    - Starts with uppercase: classes/modules/constants first
+ * 5. Within same type priority:
+ *    - Unqualified match > qualified match
+ *    - Shorter name > longer name
+ * 6. Class methods > instance methods
+ * 7. Result limit: 30
+ * 8. Minimum query length: 1 character
+ */
+
+var MAX_RESULTS = 30;
+var MIN_QUERY_LENGTH = 1;
+
+/*
+ * Scoring constants - organized in tiers where each tier dominates lower tiers.
+ * This ensures match type always beats type priority, etc.
+ *
+ * Tier 0: Exact matches (immediate return)
+ * Tier 1: Match type (prefix > substring > fuzzy)
+ * Tier 2: Exact name bonus
+ * Tier 3: Type priority (method vs class based on query case)
+ * Tier 4: Minor bonuses (top-level, class method, name length)
+ */
+var SCORE_EXACT_FULL_NAME = 1000000;  // Tier 0: Query exactly matches full_name
+var SCORE_MATCH_PREFIX    = 10000;    // Tier 1: Query is prefix of name
+var SCORE_MATCH_SUBSTRING = 5000;     // Tier 1: Query is substring of name
+var SCORE_MATCH_FUZZY     = 1000;     // Tier 1: Query chars appear in order
+var SCORE_EXACT_NAME      = 500;      // Tier 2: Name exactly equals query
+var SCORE_TYPE_PRIORITY   = 100;      // Tier 3: Preferred type (method/class)
+var SCORE_TOP_LEVEL       = 50;       // Tier 4: Top-level over namespaced
+var SCORE_CLASS_METHOD    = 10;       // Tier 4: Class method over instance method
+
+/**
+ * Check if all characters in query appear in order in target
+ * e.g., "addalias" fuzzy matches "add_foo_alias"
+ */
+function fuzzyMatch(target, query) {
+  var ti = 0;
+  for (var qi = 0; qi < query.length; qi++) {
+    ti = target.indexOf(query[qi], ti);
+    if (ti === -1) return false;
+    ti++;
+  }
+  return true;
+}
+
+/**
+ * Parse and normalize a search query
+ * @param {string} query - The raw search query
+ * @returns {Object} Parsed query with normalized form and flags
+ */
+function parseQuery(query) {
+  // Lowercase for case-insensitive matching (so "hash" finds both Hash class and #hash methods)
+  var normalized = query.toLowerCase();
+  var isNamespaceQuery = query.includes('::');
+  var isMethodQuery = query.includes('#') || query.includes('.');
+
+  // Normalize . to :: (RDoc uses :: for class methods in full_name)
+  if (query.includes('.')) {
+    normalized = normalized.replace(/\./g, '::');
+  }
+
+  return {
+    original: query,
+    normalized: normalized,
+    isNamespaceQuery: isNamespaceQuery,
+    isMethodQuery: isMethodQuery,
+    // Namespace and method queries match against full_name instead of name
+    matchesFullName: isNamespaceQuery || isMethodQuery,
+    // If query starts with lowercase, prioritize methods; otherwise prioritize classes/modules/constants
+    prioritizeMethod: !/^[A-Z]/.test(query)
+  };
+}
+
+/**
+ * Main search function
+ * @param {string} query - The search query
+ * @param {Array} index - The search index to search in
+ * @returns {Array} Array of matching entries, sorted by relevance
+ */
+function search(query, index) {
+  if (!query || query.length < MIN_QUERY_LENGTH) {
+    return [];
+  }
+
+  var q = parseQuery(query);
+  var results = [];
+
+  for (var i = 0; i < index.length; i++) {
+    var entry = index[i];
+    var score = computeScore(entry, q);
+
+    if (score !== null) {
+      results.push({ entry: entry, score: score });
+    }
+  }
+
+  results.sort(function(a, b) {
+    return b.score - a.score;
+  });
+
+  return results.slice(0, MAX_RESULTS).map(function(r) {
+    return r.entry;
+  });
+}
+
+/**
+ * Compute the relevance score for an entry
+ * @param {Object} entry - The search index entry
+ * @param {Object} q - Parsed query from parseQuery()
+ * @returns {number|null} Score or null if no match
+ */
+function computeScore(entry, q) {
+  var name = entry.name;
+  var fullName = entry.full_name;
+  var type = entry.type;
+
+  var nameLower = name.toLowerCase();
+  var fullNameLower = fullName.toLowerCase();
+
+  // Exact full_name match (e.g., "Array#filter" matches Array#filter)
+  if (q.matchesFullName && fullNameLower === q.normalized) {
+    return SCORE_EXACT_FULL_NAME;
+  }
+
+  var matchScore = 0;
+  var target = q.matchesFullName ? fullNameLower : nameLower;
+
+  if (target.startsWith(q.normalized)) {
+    matchScore = SCORE_MATCH_PREFIX;     // Prefix (e.g., "Arr" matches "Array")
+  } else if (target.includes(q.normalized)) {
+    matchScore = SCORE_MATCH_SUBSTRING;  // Substring (e.g., "ray" matches "Array")
+  } else if (fuzzyMatch(target, q.normalized)) {
+    matchScore = SCORE_MATCH_FUZZY;      // Fuzzy (e.g., "addalias" matches "add_foo_alias")
+  } else {
+    return null;
+  }
+
+  var score = matchScore;
+  var isMethod = (type === 'instance_method' || type === 'class_method');
+
+  if (q.prioritizeMethod ? isMethod : !isMethod) {
+    score += SCORE_TYPE_PRIORITY;
+  }
+
+  if (type === 'class_method') score += SCORE_CLASS_METHOD;
+  if (name === fullName) score += SCORE_TOP_LEVEL;  // Top-level (Hash) > namespaced (Foo::Hash)
+  if (nameLower === q.normalized) score += SCORE_EXACT_NAME;  // Exact name match
+  score -= name.length;
+
+  return score;
+}
+
+/**
+ * SearchRanker class for compatibility with the Search UI
+ * Provides ready() and find() interface
+ */
+function SearchRanker(index) {
+  this.index = index;
+  this.handlers = [];
+}
+
+SearchRanker.prototype.ready = function(fn) {
+  this.handlers.push(fn);
+};
+
+SearchRanker.prototype.find = function(query) {
+  var q = parseQuery(query);
+  var rawResults = search(query, this.index);
+  var results = rawResults.map(function(entry) {
+    return formatResult(entry, q);
+  });
+
+  var _this = this;
+  this.handlers.forEach(function(fn) {
+    fn.call(_this, results, true);
+  });
+};
+
+/**
+ * Format a search result entry for display
+ */
+function formatResult(entry, q) {
+  var result = {
+    title: highlightMatch(entry.full_name, q),
+    path: entry.path,
+    type: entry.type
+  };
+
+  if (entry.snippet) {
+    result.snippet = entry.snippet;
+  }
+
+  return result;
+}
+
+/**
+ * Add highlight markers (\u0001 and \u0002) to matching portions of text
+ * @param {string} text - The text to highlight
+ * @param {Object} q - Parsed query from parseQuery()
+ */
+function highlightMatch(text, q) {
+  if (!text || !q) return text;
+
+  var textLower = text.toLowerCase();
+  var query = q.normalized;
+
+  // Try contiguous match first (prefix or substring)
+  var matchIndex = textLower.indexOf(query);
+  if (matchIndex !== -1) {
+    return text.substring(0, matchIndex) +
+      '\u0001' + text.substring(matchIndex, matchIndex + query.length) + '\u0002' +
+      text.substring(matchIndex + query.length);
+  }
+
+  // Fall back to fuzzy highlight (highlight each matched character)
+  var result = '';
+  var ti = 0;
+  for (var qi = 0; qi < query.length; qi++) {
+    var charIndex = textLower.indexOf(query[qi], ti);
+    if (charIndex === -1) return text;
+    result += text.substring(ti, charIndex);
+    result += '\u0001' + text[charIndex] + '\u0002';
+    ti = charIndex + 1;
+  }
+  result += text.substring(ti);
+  return result;
+}