@tanstack/db/dist/esm/utils/cursor.js

A reactive client store for building super fast apps on sync

import { and, lt, gte, eq, or, isUndefined, isNull, not, gt } from "../query/builder/functions.js";
import { Value } from "../query/ir.js";
function isNullish(expression) {
  return or(isNull(expression), isUndefined(expression));
}
function followsBoundary(clause, value) {
  const nullish = isNullish(clause.expression);
  if (value == null) {
    return clause.compareOptions.nulls === `first` ? not(nullish) : new Value(false);
  }
  const operator = clause.compareOptions.direction === `asc` ? gt : lt;
  const comparison = operator(clause.expression, new Value(value));
  return clause.compareOptions.nulls === `last` ? or(comparison, nullish) : comparison;
}
function buildCursor(orderBy, values) {
  if (values.length === 0) return void 0;
  if (orderBy.length !== 1 || values.length !== 1) {
    throw new Error(`Only single-column cursors are supported`);
  }
  return followsBoundary(orderBy[0], values[0]);
}
function buildCursorCurrent(orderBy, values) {
  const { expression } = orderBy[0] ?? {};
  if (!expression || values.length === 0) return void 0;
  const value = values[0];
  if (value == null) return isNullish(expression);
  if (value instanceof Date) {
    if (!Number.isFinite(value.getTime())) return void 0;
    return and(
      gte(expression, new Value(value)),
      lt(expression, new Value(new Date(value.getTime() + 1)))
    );
  }
  if (typeof value === `object`) return void 0;
  return eq(expression, new Value(value));
}
function canExpressCursorOrder(orderBy, values) {
  if (orderBy.length !== 1 || values.length !== 1) return false;
  const value = values[0];
  if (value == null) return false;
  if (value instanceof Date) return Number.isFinite(value.getTime());
  if (typeof value === `string`) {
    return orderBy[0].compareOptions.stringSort === `lexical`;
  }
  return typeof value === `number` && Number.isFinite(value) || typeof value === `bigint` || typeof value === `boolean`;
}
export {
  buildCursor,
  buildCursorCurrent,
  canExpressCursorOrder
};
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