HORIZON PROJECT

'use strict';

Object.defineProperty(exports, "__esModule", {

    value: true

});

exports.default = during;

var _noop = require('lodash/noop');

var _noop2 = _interopRequireDefault(_noop);

var _onlyOnce = require('./internal/onlyOnce');

var _onlyOnce2 = _interopRequireDefault(_onlyOnce);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**

 * Like [`whilst`]{@link module:ControlFlow.whilst}, except the `test` is an asynchronous function that

 * is passed a callback in the form of `function (err, truth)`. If error is

 * passed to `test` or `fn`, the main callback is immediately called with the

 * value of the error.

 *

 * @name during

 * @static

 * @memberOf module:ControlFlow

 * @method

 * @see [async.whilst]{@link module:ControlFlow.whilst}

 * @category Control Flow

 * @param {Function} test - asynchronous truth test to perform before each

 * execution of `fn`. Invoked with (callback).

 * @param {Function} fn - A function which is called each time `test` passes.

 * The function is passed a `callback(err)`, which must be called once it has

 * completed with an optional `err` argument. Invoked with (callback).

 * @param {Function} [callback] - A callback which is called after the test

 * function has failed and repeated execution of `fn` has stopped. `callback`

 * will be passed an error, if one occured, otherwise `null`.

 * @example

 *

 * var count = 0;

 *

 * async.during(

 *     function (callback) {

 *         return callback(null, count < 5);

 *     },

 *     function (callback) {

 *         count++;

 *         setTimeout(callback, 1000);

 *     },

 *     function (err) {

 *         // 5 seconds have passed

 *     }

 * );

 */

function during(test, fn, callback) {

    callback = (0, _onlyOnce2.default)(callback || _noop2.default);

    function next(err) {

        if (err) return callback(err);

        test(check);

    }

    function check(err, truth) {

        if (err) return callback(err);

        if (!truth) return callback(null);

        fn(next);

    }

    test(check);

}

module.exports = exports['default'];