@tanstack/db/dist/cjs/query/group-by.cjs

A reactive client store for building super fast apps on sync

"use strict";
Object.defineProperty(exports, Symbol.toStringTag, { value: "Module" });
const d2mini = require("@electric-sql/d2mini");
const extractors = require("./extractors.cjs");
const utils = require("./utils.cjs");
const { sum, count, avg, min, max, median, mode } = d2mini.groupByOperators;
function processGroupBy(pipeline, query, mainTableAlias) {
  const groupByColumns = Array.isArray(query.groupBy) ? query.groupBy : [query.groupBy];
  const keyExtractor = ([_oldKey, namespacedRow]) => {
    const key = {};
    for (const column of groupByColumns) {
      if (typeof column === `string` && column.startsWith(`@`)) {
        const columnRef = column.substring(1);
        const columnName = columnRef.includes(`.`) ? columnRef.split(`.`)[1] : columnRef;
        key[columnName] = extractors.extractValueFromNamespacedRow(
          namespacedRow,
          columnRef,
          mainTableAlias
        );
      }
    }
    return key;
  };
  const aggregates = {};
  if (!query.select) {
    throw new Error(`SELECT clause is required for GROUP BY`);
  }
  for (const item of query.select) {
    if (typeof item === `object`) {
      for (const [alias, expr] of Object.entries(item)) {
        if (typeof expr === `object` && utils.isAggregateFunctionCall(expr)) {
          const functionName = Object.keys(expr)[0];
          const columnRef = expr[functionName];
          aggregates[alias] = getAggregateFunction(
            functionName,
            columnRef,
            mainTableAlias
          );
        }
      }
    }
  }
  if (Object.keys(aggregates).length > 0) {
    pipeline = pipeline.pipe(d2mini.groupBy(keyExtractor, aggregates));
  }
  return pipeline;
}
function getAggregateFunction(functionName, columnRef, mainTableAlias) {
  const valueExtractor = ([_oldKey, namespacedRow]) => {
    let value;
    if (typeof columnRef === `string` && columnRef.startsWith(`@`)) {
      value = extractors.extractValueFromNamespacedRow(
        namespacedRow,
        columnRef.substring(1),
        mainTableAlias
      );
    } else {
      value = extractors.evaluateOperandOnNamespacedRow(
        namespacedRow,
        columnRef,
        mainTableAlias
      );
    }
    return typeof value === `number` ? value : 0;
  };
  switch (functionName.toUpperCase()) {
    case `SUM`:
      return sum(valueExtractor);
    case `COUNT`:
      return count();
    // count() doesn't need a value extractor
    case `AVG`:
      return avg(valueExtractor);
    case `MIN`:
      return min(valueExtractor);
    case `MAX`:
      return max(valueExtractor);
    case `MEDIAN`:
      return median(valueExtractor);
    case `MODE`:
      return mode(valueExtractor);
    default:
      throw new Error(`Unsupported aggregate function: ${functionName}`);
  }
}
exports.getAggregateFunction = getAggregateFunction;
exports.processGroupBy = processGroupBy;
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