graphql-mocks/relay/paginate-nodes.js

Tools for setting up graphql test resolvers

'use strict';

Object.defineProperty(exports, '__esModule', {
  value: true
});

var applyCursorToEdges = require('./apply-cursor-to-edges.js');

var createEdge = require('./create-edge.js');

function paginateNodes(nodes, args, cursorForNode) {
  var _edges$, _edges;

  const {
    first,
    last,
    before,
    after
  } = args;
  const allEdges = nodes.map(node => createEdge.createEdge(node, cursorForNode(node))); // eslint-disable-next-line prefer-const

  let {
    edges,
    frontCut,
    backCut
  } = applyCursorToEdges.applyCursorsToEdges(allEdges, cursorForNode, before, after);
  let hasNextPage = backCut;
  let hasPreviousPage = frontCut;

  if (first) {
    if (first < 0) throw new Error('`first` argument must be greater than or equal to 0');

    if (edges.length > first) {
      edges = edges.slice(0, first);
      hasNextPage = true;
    }
  }

  if (last) {
    if (last < 0) throw new Error('`last` argument must be greater than or equal to 0');

    if (edges.length > last) {
      edges = edges.slice(edges.length - last, edges.length);
      hasPreviousPage = true;
    }
  }

  const startNode = (_edges$ = edges[0]) === null || _edges$ === void 0 ? void 0 : _edges$.node;
  const endNode = (_edges = edges[edges.length - 1]) === null || _edges === void 0 ? void 0 : _edges.node;
  return {
    edges: edges,
    pageInfo: {
      hasNextPage,
      hasPreviousPage,
      startCursor: startNode ? cursorForNode(startNode) : null,
      endCursor: endNode ? cursorForNode(endNode) : null
    }
  };
}

exports.paginateNodes = paginateNodes;
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