@tanstack/db/dist/esm/indexes/auto-index.js

A reactive client store for building super fast apps on sync

import { BTreeIndex } from "./btree-index.js";
function ensureIndexForExpression(expression, collection) {
  if (collection.config.autoIndex !== `eager`) {
    return;
  }
  if (collection.status === `loading` || collection.status === `initialCommit`) {
    return;
  }
  const indexableExpressions = extractIndexableExpressions(expression);
  for (const { fieldName, fieldPath } of indexableExpressions) {
    const existingIndex = Array.from(collection.indexes.values()).find(
      (index) => index.matchesField(fieldPath)
    );
    if (existingIndex) {
      continue;
    }
    try {
      collection.createIndex((row) => row[fieldName], {
        name: `auto_${fieldName}`,
        indexType: BTreeIndex
      });
    } catch (error) {
      console.warn(
        `Failed to create auto-index for field "${fieldName}":`,
        error
      );
    }
  }
}
function extractIndexableExpressions(expression) {
  const results = [];
  function extractFromExpression(expr) {
    if (expr.type !== `func`) {
      return;
    }
    const func = expr;
    if (func.name === `and`) {
      for (const arg of func.args) {
        extractFromExpression(arg);
      }
      return;
    }
    const supportedOperations = [`eq`, `gt`, `gte`, `lt`, `lte`, `in`];
    if (!supportedOperations.includes(func.name)) {
      return;
    }
    if (func.args.length < 1 || func.args[0].type !== `ref`) {
      return;
    }
    const fieldRef = func.args[0];
    const fieldPath = fieldRef.path;
    if (fieldPath.length !== 1) {
      return;
    }
    const fieldName = fieldPath[0];
    results.push({ fieldName, fieldPath });
  }
  extractFromExpression(expression);
  return results;
}
export {
  ensureIndexForExpression
};
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