relay-runtime/util/getPaginationVariables.js.flow

A core runtime for building GraphQL-driven applications.

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow strict-local
 * @format
 * @oncall relay
 */

'use strict';

import type {ReaderPaginationMetadata} from './ReaderNode';
import type {Variables} from './RelayRuntimeTypes';

const invariant = require('invariant');
const warning = require('warning');

export type Direction = 'forward' | 'backward';

function getPaginationVariables(
  direction: Direction,
  count: number,
  cursor: ?string,
  baseVariables: Variables,
  extraVariables: Variables,
  paginationMetadata: ReaderPaginationMetadata,
): {[string]: mixed, ...} {
  const {backward: backwardMetadata, forward: forwardMetadata} =
    paginationMetadata;

  if (direction === 'backward') {
    invariant(
      backwardMetadata != null &&
        backwardMetadata.count != null &&
        backwardMetadata.cursor != null,
      'Relay: Expected backward pagination metadata to be available. ' +
        "If you're seeing this, this is likely a bug in Relay.",
    );
    warning(
      !extraVariables.hasOwnProperty(backwardMetadata.cursor),
      'Relay: `UNSTABLE_extraVariables` provided by caller should not ' +
        'contain cursor variable `%s`. This variable is automatically ' +
        'determined by Relay.',
      backwardMetadata.cursor,
    );
    warning(
      !extraVariables.hasOwnProperty(backwardMetadata.count),
      'Relay: `UNSTABLE_extraVariables` provided by caller should not ' +
        'contain count variable `%s`. This variable is automatically ' +
        'determined by Relay.',
      backwardMetadata.count,
    );
    const paginationVariables = {
      ...baseVariables,
      ...extraVariables,
      [backwardMetadata.cursor]: cursor,
      [backwardMetadata.count]: count,
    };
    if (forwardMetadata && forwardMetadata.cursor) {
      paginationVariables[forwardMetadata.cursor] = null;
    }
    if (forwardMetadata && forwardMetadata.count) {
      paginationVariables[forwardMetadata.count] = null;
    }
    return paginationVariables;
  }

  invariant(
    forwardMetadata != null &&
      forwardMetadata.count != null &&
      forwardMetadata.cursor != null,
    'Relay: Expected forward pagination metadata to be available. ' +
      "If you're seeing this, this is likely a bug in Relay.",
  );
  warning(
    !extraVariables.hasOwnProperty(forwardMetadata.cursor),
    'Relay: `UNSTABLE_extraVariables` provided by caller should not ' +
      'contain cursor variable `%s`. This variable is automatically ' +
      'determined by Relay.',
    forwardMetadata.cursor,
  );
  warning(
    !extraVariables.hasOwnProperty(forwardMetadata.count),
    'Relay: `UNSTABLE_extraVariables` provided by caller should not ' +
      'contain count variable `%s`. This variable is automatically ' +
      'determined by Relay.',
    forwardMetadata.count,
  );
  const paginationVariables = {
    ...baseVariables,
    ...extraVariables,
    [forwardMetadata.cursor]: cursor,
    [forwardMetadata.count]: count,
  };
  if (backwardMetadata && backwardMetadata.cursor) {
    paginationVariables[backwardMetadata.cursor] = null;
  }
  if (backwardMetadata && backwardMetadata.count) {
    paginationVariables[backwardMetadata.count] = null;
  }
  return paginationVariables;
}

module.exports = getPaginationVariables;