@wordpress/core-data/build/batch/create-batch.js

Access to and manipulation of core WordPress entities.

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = createBatch;
var _defaultProcessor = _interopRequireDefault(require("./default-processor"));
/**
 * Internal dependencies
 */

/**
 * Creates a batch, which can be used to combine multiple API requests into one
 * API request using the WordPress batch processing API (/v1/batch).
 *
 * ```
 * const batch = createBatch();
 * const dunePromise = batch.add( {
 *   path: '/v1/books',
 *   method: 'POST',
 *   data: { title: 'Dune' }
 * } );
 * const lotrPromise = batch.add( {
 *   path: '/v1/books',
 *   method: 'POST',
 *   data: { title: 'Lord of the Rings' }
 * } );
 * const isSuccess = await batch.run(); // Sends one POST to /v1/batch.
 * if ( isSuccess ) {
 *   console.log(
 *     'Saved two books:',
 *     await dunePromise,
 *     await lotrPromise
 *   );
 * }
 * ```
 *
 * @param {Function} [processor] Processor function. Can be used to replace the
 *                               default functionality which is to send an API
 *                               request to /v1/batch. Is given an array of
 *                               inputs and must return a promise that
 *                               resolves to an array of objects containing
 *                               either `output` or `error`.
 */
function createBatch(processor = _defaultProcessor.default) {
  let lastId = 0;
  /** @type {Array<{ input: any; resolve: ( value: any ) => void; reject: ( error: any ) => void }>} */
  let queue = [];
  const pending = new ObservableSet();
  return {
    /**
     * Adds an input to the batch and returns a promise that is resolved or
     * rejected when the input is processed by `batch.run()`.
     *
     * You may also pass a thunk which allows inputs to be added
     * asynchronously.
     *
     * ```
     * // Both are allowed:
     * batch.add( { path: '/v1/books', ... } );
     * batch.add( ( add ) => add( { path: '/v1/books', ... } ) );
     * ```
     *
     * If a thunk is passed, `batch.run()` will pause until either:
     *
     * - The thunk calls its `add` argument, or;
     * - The thunk returns a promise and that promise resolves, or;
     * - The thunk returns a non-promise.
     *
     * @param {any|Function} inputOrThunk Input to add or thunk to execute.
     *
     * @return {Promise|any} If given an input, returns a promise that
     *                       is resolved or rejected when the batch is
     *                       processed. If given a thunk, returns the return
     *                       value of that thunk.
     */
    add(inputOrThunk) {
      const id = ++lastId;
      pending.add(id);
      const add = input => new Promise((resolve, reject) => {
        queue.push({
          input,
          resolve,
          reject
        });
        pending.delete(id);
      });
      if (typeof inputOrThunk === 'function') {
        return Promise.resolve(inputOrThunk(add)).finally(() => {
          pending.delete(id);
        });
      }
      return add(inputOrThunk);
    },
    /**
     * Runs the batch. This calls `batchProcessor` and resolves or rejects
     * all promises returned by `add()`.
     *
     * @return {Promise<boolean>} A promise that resolves to a boolean that is true
     *                   if the processor returned no errors.
     */
    async run() {
      if (pending.size) {
        await new Promise(resolve => {
          const unsubscribe = pending.subscribe(() => {
            if (!pending.size) {
              unsubscribe();
              resolve(undefined);
            }
          });
        });
      }
      let results;
      try {
        results = await processor(queue.map(({
          input
        }) => input));
        if (results.length !== queue.length) {
          throw new Error('run: Array returned by processor must be same size as input array.');
        }
      } catch (error) {
        for (const {
          reject
        } of queue) {
          reject(error);
        }
        throw error;
      }
      let isSuccess = true;
      results.forEach((result, key) => {
        const queueItem = queue[key];
        if (result?.error) {
          queueItem?.reject(result.error);
          isSuccess = false;
        } else {
          var _result$output;
          queueItem?.resolve((_result$output = result?.output) !== null && _result$output !== void 0 ? _result$output : result);
        }
      });
      queue = [];
      return isSuccess;
    }
  };
}
class ObservableSet {
  constructor(...args) {
    this.set = new Set(...args);
    this.subscribers = new Set();
  }
  get size() {
    return this.set.size;
  }
  add(value) {
    this.set.add(value);
    this.subscribers.forEach(subscriber => subscriber());
    return this;
  }
  delete(value) {
    const isSuccess = this.set.delete(value);
    this.subscribers.forEach(subscriber => subscriber());
    return isSuccess;
  }
  subscribe(subscriber) {
    this.subscribers.add(subscriber);
    return () => {
      this.subscribers.delete(subscriber);
    };
  }
}
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