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206 lines
8.4 KiB
206 lines
8.4 KiB
"use strict";
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/*!
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* Copyright 2015 Google Inc. All Rights Reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.ResourceStream = exports.paginator = exports.Paginator = void 0;
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/*!
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* @module common/paginator
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*/
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const arrify = require("arrify");
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const extend = require("extend");
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const resource_stream_1 = require("./resource-stream");
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Object.defineProperty(exports, "ResourceStream", { enumerable: true, get: function () { return resource_stream_1.ResourceStream; } });
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/*! Developer Documentation
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*
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* paginator is used to auto-paginate `nextQuery` methods as well as
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* streamifying them.
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*
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* Before:
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*
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* search.query('done=true', function(err, results, nextQuery) {
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* search.query(nextQuery, function(err, results, nextQuery) {});
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* });
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*
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* After:
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*
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* search.query('done=true', function(err, results) {});
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*
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* Methods to extend should be written to accept callbacks and return a
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* `nextQuery`.
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*/
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class Paginator {
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/**
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* Cache the original method, then overwrite it on the Class's prototype.
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*
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* @param {function} Class - The parent class of the methods to extend.
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* @param {string|string[]} methodNames - Name(s) of the methods to extend.
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*/
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// tslint:disable-next-line:variable-name
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extend(Class, methodNames) {
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methodNames = arrify(methodNames);
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methodNames.forEach(methodName => {
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const originalMethod = Class.prototype[methodName];
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// map the original method to a private member
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Class.prototype[methodName + '_'] = originalMethod;
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// overwrite the original to auto-paginate
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/* eslint-disable @typescript-eslint/no-explicit-any */
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Class.prototype[methodName] = function (...args) {
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const parsedArguments = paginator.parseArguments_(args);
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return paginator.run_(parsedArguments, originalMethod.bind(this));
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};
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});
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}
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/**
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* Wraps paginated API calls in a readable object stream.
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*
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* This method simply calls the nextQuery recursively, emitting results to a
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* stream. The stream ends when `nextQuery` is null.
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*
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* `maxResults` will act as a cap for how many results are fetched and emitted
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* to the stream.
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*
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* @param {string} methodName - Name of the method to streamify.
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* @return {function} - Wrapped function.
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*/
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/* eslint-disable @typescript-eslint/no-explicit-any */
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streamify(methodName) {
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return function (
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/* eslint-disable @typescript-eslint/no-explicit-any */
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...args) {
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const parsedArguments = paginator.parseArguments_(args);
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const originalMethod = this[methodName + '_'] || this[methodName];
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return paginator.runAsStream_(parsedArguments, originalMethod.bind(this));
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};
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}
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/**
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* Parse a pseudo-array `arguments` for a query and callback.
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*
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* @param {array} args - The original `arguments` pseduo-array that the original
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* method received.
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*/
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/* eslint-disable @typescript-eslint/no-explicit-any */
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parseArguments_(args) {
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let query;
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let autoPaginate = true;
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let maxApiCalls = -1;
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let maxResults = -1;
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let callback;
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const firstArgument = args[0];
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const lastArgument = args[args.length - 1];
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if (typeof firstArgument === 'function') {
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callback = firstArgument;
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}
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else {
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query = firstArgument;
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}
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if (typeof lastArgument === 'function') {
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callback = lastArgument;
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}
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if (typeof query === 'object') {
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query = extend(true, {}, query);
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// Check if the user only asked for a certain amount of results.
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if (query.maxResults && typeof query.maxResults === 'number') {
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// `maxResults` is used API-wide.
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maxResults = query.maxResults;
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}
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else if (typeof query.pageSize === 'number') {
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// `pageSize` is Pub/Sub's `maxResults`.
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maxResults = query.pageSize;
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}
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if (query.maxApiCalls && typeof query.maxApiCalls === 'number') {
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maxApiCalls = query.maxApiCalls;
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delete query.maxApiCalls;
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}
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// maxResults is the user specified limit.
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if (maxResults !== -1 || query.autoPaginate === false) {
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autoPaginate = false;
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}
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}
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const parsedArguments = {
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query: query || {},
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autoPaginate,
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maxApiCalls,
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maxResults,
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callback,
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};
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parsedArguments.streamOptions = extend(true, {}, parsedArguments.query);
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delete parsedArguments.streamOptions.autoPaginate;
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delete parsedArguments.streamOptions.maxResults;
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delete parsedArguments.streamOptions.pageSize;
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return parsedArguments;
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}
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/**
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* This simply checks to see if `autoPaginate` is set or not, if it's true
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* then we buffer all results, otherwise simply call the original method.
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*
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* @param {array} parsedArguments - Parsed arguments from the original method
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* call.
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* @param {object=|string=} parsedArguments.query - Query object. This is most
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* commonly an object, but to make the API more simple, it can also be a
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* string in some places.
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* @param {function=} parsedArguments.callback - Callback function.
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* @param {boolean} parsedArguments.autoPaginate - Auto-pagination enabled.
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* @param {boolean} parsedArguments.maxApiCalls - Maximum API calls to make.
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* @param {number} parsedArguments.maxResults - Maximum results to return.
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* @param {function} originalMethod - The cached method that accepts a callback
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* and returns `nextQuery` to receive more results.
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*/
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run_(parsedArguments, originalMethod) {
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const query = parsedArguments.query;
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const callback = parsedArguments.callback;
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if (!parsedArguments.autoPaginate) {
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return originalMethod(query, callback);
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}
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const results = new Array();
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const promise = new Promise((resolve, reject) => {
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paginator
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.runAsStream_(parsedArguments, originalMethod)
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.on('error', reject)
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.on('data', (data) => results.push(data))
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.on('end', () => resolve(results));
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});
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if (!callback) {
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return promise.then(results => [results]);
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}
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promise.then(results => callback(null, results), (err) => callback(err));
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}
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/**
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* This method simply calls the nextQuery recursively, emitting results to a
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* stream. The stream ends when `nextQuery` is null.
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*
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* `maxResults` will act as a cap for how many results are fetched and emitted
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* to the stream.
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*
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* @param {object=|string=} parsedArguments.query - Query object. This is most
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* commonly an object, but to make the API more simple, it can also be a
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* string in some places.
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* @param {function=} parsedArguments.callback - Callback function.
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* @param {boolean} parsedArguments.autoPaginate - Auto-pagination enabled.
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* @param {boolean} parsedArguments.maxApiCalls - Maximum API calls to make.
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* @param {number} parsedArguments.maxResults - Maximum results to return.
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* @param {function} originalMethod - The cached method that accepts a callback
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* and returns `nextQuery` to receive more results.
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* @return {stream} - Readable object stream.
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*/
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/* eslint-disable @typescript-eslint/no-explicit-any */
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runAsStream_(parsedArguments, originalMethod) {
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return new resource_stream_1.ResourceStream(parsedArguments, originalMethod);
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}
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}
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exports.Paginator = Paginator;
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const paginator = new Paginator();
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exports.paginator = paginator;
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//# sourceMappingURL=index.js.map
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