1 | ;
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2 |
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3 | Object.defineProperty(exports, "__esModule", {
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4 | value: true
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5 | });
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6 |
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7 | exports.default = function (worker, concurrency) {
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8 | var _worker = (0, _wrapAsync2.default)(worker);
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9 | return (0, _queue2.default)((items, cb) => {
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10 | _worker(items[0], cb);
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11 | }, concurrency, 1);
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12 | };
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13 |
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14 | var _queue = require('./internal/queue');
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15 |
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16 | var _queue2 = _interopRequireDefault(_queue);
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17 |
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18 | var _wrapAsync = require('./internal/wrapAsync');
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19 |
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20 | var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
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21 |
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22 | function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
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23 |
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24 | module.exports = exports['default'];
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25 |
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26 | /**
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27 | * A queue of tasks for the worker function to complete.
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28 | * @typedef {Iterable} QueueObject
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29 | * @memberOf module:ControlFlow
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30 | * @property {Function} length - a function returning the number of items
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31 | * waiting to be processed. Invoke with `queue.length()`.
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32 | * @property {boolean} started - a boolean indicating whether or not any
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33 | * items have been pushed and processed by the queue.
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34 | * @property {Function} running - a function returning the number of items
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35 | * currently being processed. Invoke with `queue.running()`.
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36 | * @property {Function} workersList - a function returning the array of items
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37 | * currently being processed. Invoke with `queue.workersList()`.
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38 | * @property {Function} idle - a function returning false if there are items
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39 | * waiting or being processed, or true if not. Invoke with `queue.idle()`.
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40 | * @property {number} concurrency - an integer for determining how many `worker`
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41 | * functions should be run in parallel. This property can be changed after a
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42 | * `queue` is created to alter the concurrency on-the-fly.
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43 | * @property {number} payload - an integer that specifies how many items are
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44 | * passed to the worker function at a time. only applies if this is a
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45 | * [cargo]{@link module:ControlFlow.cargo} object
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46 | * @property {AsyncFunction} push - add a new task to the `queue`. Calls `callback`
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47 | * once the `worker` has finished processing the task. Instead of a single task,
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48 | * a `tasks` array can be submitted. The respective callback is used for every
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49 | * task in the list. Invoke with `queue.push(task, [callback])`,
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50 | * @property {AsyncFunction} unshift - add a new task to the front of the `queue`.
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51 | * Invoke with `queue.unshift(task, [callback])`.
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52 | * @property {AsyncFunction} pushAsync - the same as `q.push`, except this returns
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53 | * a promise that rejects if an error occurs.
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54 | * @property {AsyncFunction} unshirtAsync - the same as `q.unshift`, except this returns
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55 | * a promise that rejects if an error occurs.
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56 | * @property {Function} remove - remove items from the queue that match a test
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57 | * function. The test function will be passed an object with a `data` property,
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58 | * and a `priority` property, if this is a
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59 | * [priorityQueue]{@link module:ControlFlow.priorityQueue} object.
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60 | * Invoked with `queue.remove(testFn)`, where `testFn` is of the form
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61 | * `function ({data, priority}) {}` and returns a Boolean.
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62 | * @property {Function} saturated - a function that sets a callback that is
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63 | * called when the number of running workers hits the `concurrency` limit, and
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64 | * further tasks will be queued. If the callback is omitted, `q.saturated()`
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65 | * returns a promise for the next occurrence.
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66 | * @property {Function} unsaturated - a function that sets a callback that is
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67 | * called when the number of running workers is less than the `concurrency` &
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68 | * `buffer` limits, and further tasks will not be queued. If the callback is
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69 | * omitted, `q.unsaturated()` returns a promise for the next occurrence.
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70 | * @property {number} buffer - A minimum threshold buffer in order to say that
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71 | * the `queue` is `unsaturated`.
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72 | * @property {Function} empty - a function that sets a callback that is called
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73 | * when the last item from the `queue` is given to a `worker`. If the callback
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74 | * is omitted, `q.empty()` returns a promise for the next occurrence.
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75 | * @property {Function} drain - a function that sets a callback that is called
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76 | * when the last item from the `queue` has returned from the `worker`. If the
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77 | * callback is omitted, `q.drain()` returns a promise for the next occurrence.
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78 | * @property {Function} error - a function that sets a callback that is called
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79 | * when a task errors. Has the signature `function(error, task)`. If the
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80 | * callback is omitted, `error()` returns a promise that rejects on the next
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81 | * error.
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82 | * @property {boolean} paused - a boolean for determining whether the queue is
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83 | * in a paused state.
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84 | * @property {Function} pause - a function that pauses the processing of tasks
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85 | * until `resume()` is called. Invoke with `queue.pause()`.
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86 | * @property {Function} resume - a function that resumes the processing of
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87 | * queued tasks when the queue is paused. Invoke with `queue.resume()`.
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88 | * @property {Function} kill - a function that removes the `drain` callback and
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89 | * empties remaining tasks from the queue forcing it to go idle. No more tasks
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90 | * should be pushed to the queue after calling this function. Invoke with `queue.kill()`.
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91 | *
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92 | * @example
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93 | * const q = aync.queue(worker, 2)
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94 | * q.push(item1)
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95 | * q.push(item2)
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96 | * q.push(item3)
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97 | * // queues are iterable, spread into an array to inspect
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98 | * const items = [...q] // [item1, item2, item3]
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99 | * // or use for of
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100 | * for (let item of q) {
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101 | * console.log(item)
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102 | * }
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103 | *
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104 | * q.drain(() => {
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105 | * console.log('all done')
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106 | * })
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107 | * // or
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108 | * await q.drain()
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109 | */
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110 |
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111 | /**
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112 | * Creates a `queue` object with the specified `concurrency`. Tasks added to the
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113 | * `queue` are processed in parallel (up to the `concurrency` limit). If all
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114 | * `worker`s are in progress, the task is queued until one becomes available.
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115 | * Once a `worker` completes a `task`, that `task`'s callback is called.
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116 | *
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117 | * @name queue
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118 | * @static
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119 | * @memberOf module:ControlFlow
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120 | * @method
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121 | * @category Control Flow
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122 | * @param {AsyncFunction} worker - An async function for processing a queued task.
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123 | * If you want to handle errors from an individual task, pass a callback to
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124 | * `q.push()`. Invoked with (task, callback).
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125 | * @param {number} [concurrency=1] - An `integer` for determining how many
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126 | * `worker` functions should be run in parallel. If omitted, the concurrency
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127 | * defaults to `1`. If the concurrency is `0`, an error is thrown.
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128 | * @returns {module:ControlFlow.QueueObject} A queue object to manage the tasks. Callbacks can be
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129 | * attached as certain properties to listen for specific events during the
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130 | * lifecycle of the queue.
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131 | * @example
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132 | *
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133 | * // create a queue object with concurrency 2
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134 | * var q = async.queue(function(task, callback) {
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135 | * console.log('hello ' + task.name);
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136 | * callback();
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137 | * }, 2);
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138 | *
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139 | * // assign a callback
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140 | * q.drain(function() {
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141 | * console.log('all items have been processed');
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142 | * });
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143 | * // or await the end
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144 | * await q.drain()
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145 | *
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146 | * // assign an error callback
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147 | * q.error(function(err, task) {
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148 | * console.error('task experienced an error');
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149 | * });
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150 | *
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151 | * // add some items to the queue
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152 | * q.push({name: 'foo'}, function(err) {
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153 | * console.log('finished processing foo');
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154 | * });
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155 | * // callback is optional
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156 | * q.push({name: 'bar'});
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157 | *
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158 | * // add some items to the queue (batch-wise)
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159 | * q.push([{name: 'baz'},{name: 'bay'},{name: 'bax'}], function(err) {
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160 | * console.log('finished processing item');
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161 | * });
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162 | *
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163 | * // add some items to the front of the queue
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164 | * q.unshift({name: 'bar'}, function (err) {
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165 | * console.log('finished processing bar');
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166 | * });
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167 | */ |
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