@tanstack/db/dist/cjs/collection/change-events.cjs.map

A reactive client store for building super fast apps on sync

{"version":3,"file":"change-events.cjs","sources":["../../../src/collection/change-events.ts"],"sourcesContent":["import {\n  createSingleRowRefProxy,\n  toExpression,\n} from '../query/builder/ref-proxy'\nimport {\n  compileSingleRowExpression,\n  toBooleanPredicate,\n} from '../query/compiler/evaluators.js'\nimport {\n  findIndexForField,\n  optimizeExpressionWithIndexes,\n} from '../utils/index-optimization.js'\nimport { ensureIndexForField } from '../indexes/auto-index.js'\nimport { makeComparator } from '../utils/comparison.js'\nimport { buildCompareOptions } from '../query/compiler/order-by'\nimport type {\n  ChangeMessage,\n  CollectionLike,\n  CurrentStateAsChangesOptions,\n  SubscribeChangesOptions,\n} from '../types'\nimport type { CollectionImpl } from './index.js'\nimport type { SingleRowRefProxy } from '../query/builder/ref-proxy'\nimport type { BasicExpression, OrderBy } from '../query/ir.js'\n\n/**\n * Returns the current state of the collection as an array of changes\n * @param collection - The collection to get changes from\n * @param options - Options including optional where filter, orderBy, and limit\n * @returns An array of changes\n * @example\n * // Get all items as changes\n * const allChanges = currentStateAsChanges(collection)\n *\n * // Get only items matching a condition\n * const activeChanges = currentStateAsChanges(collection, {\n *   where: (row) => row.status === 'active'\n * })\n *\n * // Get only items using a pre-compiled expression\n * const activeChanges = currentStateAsChanges(collection, {\n *   where: eq(row.status, 'active')\n * })\n *\n * // Get items ordered by name with limit\n * const topUsers = currentStateAsChanges(collection, {\n *   orderBy: [{ expression: row.name, compareOptions: { direction: 'asc' } }],\n *   limit: 10\n * })\n *\n * // Get active users ordered by score (highest score first)\n * const topActiveUsers = currentStateAsChanges(collection, {\n *   where: eq(row.status, 'active'),\n *   orderBy: [{ expression: row.score, compareOptions: { direction: 'desc' } }],\n * })\n */\nexport function currentStateAsChanges<\n  T extends object,\n  TKey extends string | number,\n>(\n  collection: CollectionLike<T, TKey>,\n  options: CurrentStateAsChangesOptions = {},\n): Array<ChangeMessage<T>> | void {\n  // Helper function to collect filtered results\n  const collectFilteredResults = (\n    filterFn?: (value: T) => boolean,\n  ): Array<ChangeMessage<T>> => {\n    const result: Array<ChangeMessage<T>> = []\n    for (const [key, value] of collection.entries()) {\n      // If no filter function is provided, include all items\n      if (filterFn?.(value) ?? true) {\n        result.push({\n          type: `insert`,\n          key,\n          value,\n        })\n      }\n    }\n    return result\n  }\n\n  // Validate that limit without orderBy doesn't happen\n  if (options.limit !== undefined && !options.orderBy) {\n    throw new Error(`limit cannot be used without orderBy`)\n  }\n\n  // First check if orderBy is present (optionally with limit)\n  if (options.orderBy) {\n    // Create where filter function if present\n    const whereFilter = options.where\n      ? createFilterFunctionFromExpression(options.where)\n      : undefined\n\n    // Get ordered keys using index optimization when possible\n    const orderedKeys = getOrderedKeys(\n      collection,\n      options.orderBy,\n      options.limit,\n      whereFilter,\n      options.optimizedOnly,\n    )\n\n    if (orderedKeys === undefined) {\n      // `getOrderedKeys` returned undefined because we asked for `optimizedOnly` and there was no index to use\n      return\n    }\n\n    // Convert keys to change messages\n    const result: Array<ChangeMessage<T>> = []\n    for (const key of orderedKeys) {\n      const value = collection.get(key)\n      if (value !== undefined) {\n        result.push({\n          type: `insert`,\n          key,\n          value,\n        })\n      }\n    }\n    return result\n  }\n\n  // If no orderBy OR orderBy optimization failed, use where clause optimization\n  if (!options.where) {\n    // No filtering, return all items\n    return collectFilteredResults()\n  }\n\n  // There's a where clause, let's see if we can use an index\n  try {\n    const expression: BasicExpression<boolean> = options.where\n\n    // Try to optimize the query using indexes\n    const optimizationResult = optimizeExpressionWithIndexes(\n      expression,\n      collection,\n    )\n\n    if (optimizationResult.canOptimize) {\n      // Use index optimization\n      const result: Array<ChangeMessage<T>> = []\n      for (const key of optimizationResult.matchingKeys) {\n        const value = collection.get(key)\n        if (value !== undefined) {\n          result.push({\n            type: `insert`,\n            key,\n            value,\n          })\n        }\n      }\n      return result\n    } else {\n      if (options.optimizedOnly) {\n        return\n      }\n\n      const filterFn = createFilterFunctionFromExpression(expression)\n      return collectFilteredResults(filterFn)\n    }\n  } catch (error) {\n    // If anything goes wrong with the where clause, fall back to full scan\n    console.warn(\n      `${collection.id ? `[${collection.id}] ` : ``}Error processing where clause, falling back to full scan:`,\n      error,\n    )\n\n    const filterFn = createFilterFunctionFromExpression(options.where)\n\n    if (options.optimizedOnly) {\n      return\n    }\n\n    return collectFilteredResults(filterFn)\n  }\n}\n\n/**\n * Creates a filter function from a where callback\n * @param whereCallback - The callback function that defines the filter condition\n * @returns A function that takes an item and returns true if it matches the filter\n */\nexport function createFilterFunction<T extends object>(\n  whereCallback: (row: SingleRowRefProxy<T>) => any,\n): (item: T) => boolean {\n  return (item: T): boolean => {\n    try {\n      // First try the RefProxy approach for query builder functions\n      const singleRowRefProxy = createSingleRowRefProxy<T>()\n      const whereExpression = whereCallback(singleRowRefProxy)\n      const expression = toExpression(whereExpression)\n      const evaluator = compileSingleRowExpression(expression)\n      const result = evaluator(item as Record<string, unknown>)\n      // WHERE clauses should always evaluate to boolean predicates (Kevin's feedback)\n      return toBooleanPredicate(result)\n    } catch {\n      // If RefProxy approach fails (e.g., arithmetic operations), fall back to direct evaluation\n      try {\n        // Create a simple proxy that returns actual values for arithmetic operations\n        const simpleProxy = new Proxy(item as any, {\n          get(target, prop) {\n            return target[prop]\n          },\n        }) as SingleRowRefProxy<T>\n\n        const result = whereCallback(simpleProxy)\n        return toBooleanPredicate(result)\n      } catch {\n        // If both approaches fail, exclude the item\n        return false\n      }\n    }\n  }\n}\n\n/**\n * Creates a filter function from a pre-compiled expression\n * @param expression - The pre-compiled expression to evaluate\n * @returns A function that takes an item and returns true if it matches the filter\n */\nexport function createFilterFunctionFromExpression<T extends object>(\n  expression: BasicExpression<boolean>,\n): (item: T) => boolean {\n  // Compile expression once when filter function is created, not on every invocation\n  const evaluator = compileSingleRowExpression(expression)\n\n  return (item: T): boolean => {\n    try {\n      const result = evaluator(item as Record<string, unknown>)\n      return toBooleanPredicate(result)\n    } catch {\n      // If evaluation fails, exclude the item\n      return false\n    }\n  }\n}\n\n/**\n * Creates a filtered callback that only calls the original callback with changes that match the where clause\n * @param originalCallback - The original callback to filter\n * @param options - The subscription options containing the where clause\n * @returns A filtered callback function\n */\nexport function createFilteredCallback<T extends object>(\n  originalCallback: (changes: Array<ChangeMessage<T>>) => void,\n  options: SubscribeChangesOptions,\n): (changes: Array<ChangeMessage<T>>) => void {\n  const filterFn = createFilterFunctionFromExpression(options.whereExpression!)\n\n  return (changes: Array<ChangeMessage<T>>) => {\n    const filteredChanges: Array<ChangeMessage<T>> = []\n\n    for (const change of changes) {\n      if (change.type === `insert`) {\n        // For inserts, check if the new value matches the filter\n        if (filterFn(change.value)) {\n          filteredChanges.push(change)\n        }\n      } else if (change.type === `update`) {\n        // For updates, we need to check both old and new values\n        const newValueMatches = filterFn(change.value)\n        const oldValueMatches = change.previousValue\n          ? filterFn(change.previousValue)\n          : false\n\n        if (newValueMatches && oldValueMatches) {\n          // Both old and new match: emit update\n          filteredChanges.push(change)\n        } else if (newValueMatches && !oldValueMatches) {\n          // New matches but old didn't: emit insert\n          filteredChanges.push({\n            ...change,\n            type: `insert`,\n          })\n        } else if (!newValueMatches && oldValueMatches) {\n          // Old matched but new doesn't: emit delete\n          filteredChanges.push({\n            ...change,\n            type: `delete`,\n            value: change.previousValue!, // Use the previous value for the delete\n          })\n        }\n        // If neither matches, don't emit anything\n      } else {\n        // For deletes, include if the previous value would have matched\n        // (so subscribers know something they were tracking was deleted)\n        if (filterFn(change.value)) {\n          filteredChanges.push(change)\n        }\n      }\n    }\n\n    // Always call the original callback if we have filtered changes OR\n    // if the original changes array was empty (which indicates a ready signal)\n    if (filteredChanges.length > 0 || changes.length === 0) {\n      originalCallback(filteredChanges)\n    }\n  }\n}\n\n/**\n * Gets ordered keys from a collection using index optimization when possible\n * @param collection - The collection to get keys from\n * @param orderBy - The order by clause\n * @param limit - Optional limit on number of keys to return\n * @param whereFilter - Optional filter function to apply while traversing\n * @returns Array of keys in sorted order\n */\nfunction getOrderedKeys<T extends object, TKey extends string | number>(\n  collection: CollectionLike<T, TKey>,\n  orderBy: OrderBy,\n  limit?: number,\n  whereFilter?: (item: T) => boolean,\n  optimizedOnly?: boolean,\n): Array<TKey> | undefined {\n  // For single-column orderBy on a ref expression, try index optimization\n  if (orderBy.length === 1) {\n    const clause = orderBy[0]!\n    const orderByExpression = clause.expression\n\n    if (orderByExpression.type === `ref`) {\n      const propRef = orderByExpression\n      const fieldPath = propRef.path\n      const compareOpts = buildCompareOptions(clause, collection)\n\n      // Ensure index exists for this field\n      ensureIndexForField(\n        fieldPath[0]!,\n        fieldPath,\n        collection as CollectionImpl<T, TKey>,\n        compareOpts,\n      )\n\n      // Find the index\n      const index = findIndexForField(collection, fieldPath, compareOpts)\n\n      if (index && index.supports(`gt`)) {\n        // Use index optimization\n        const filterFn = (key: TKey): boolean => {\n          const value = collection.get(key)\n          if (value === undefined) {\n            return false\n          }\n          return whereFilter?.(value) ?? true\n        }\n\n        // Take the keys that match the filter and limit\n        // if no limit is provided `index.keyCount` is used,\n        // i.e. we will take all keys that match the filter\n        return index.take(limit ?? index.keyCount, undefined, filterFn)\n      }\n    }\n  }\n\n  if (optimizedOnly) {\n    return\n  }\n\n  // Fallback: collect all items and sort in memory\n  const allItems: Array<{ key: TKey; value: T }> = []\n  for (const [key, value] of collection.entries()) {\n    if (whereFilter?.(value) ?? true) {\n      allItems.push({ key, value })\n    }\n  }\n\n  // Sort using makeComparator\n  const compare = (a: { key: TKey; value: T }, b: { key: TKey; value: T }) => {\n    for (const clause of orderBy) {\n      const compareFn = makeComparator(clause.compareOptions)\n\n      // Extract values for comparison\n      const aValue = extractValueFromItem(a.value, clause.expression)\n      const bValue = extractValueFromItem(b.value, clause.expression)\n\n      const result = compareFn(aValue, bValue)\n      if (result !== 0) {\n        return result\n      }\n    }\n    return 0\n  }\n\n  allItems.sort(compare)\n  const sortedKeys = allItems.map((item) => item.key)\n\n  // Apply limit if provided\n  if (limit !== undefined) {\n    return sortedKeys.slice(0, limit)\n  }\n\n  // if no limit is provided, we will return all keys\n  return sortedKeys\n}\n\n/**\n * Helper function to extract a value from an item based on an expression\n */\nfunction extractValueFromItem(item: any, expression: BasicExpression): any {\n  if (expression.type === `ref`) {\n    const propRef = expression\n    let value = item\n    for (const pathPart of propRef.path) {\n      value = value?.[pathPart]\n    }\n    return value\n  } else if (expression.type === `val`) {\n    return expression.value\n  } else {\n    // It must be a function\n    const evaluator = compileSingleRowExpression(expression)\n    return evaluator(item as Record<string, unknown>)\n  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