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import noop from 'lodash/noop';
import rest from 'lodash/_baseRest';
import onlyOnce from './internal/onlyOnce';
/**
* Repeatedly call `iteratee`, while `test` returns `true`. Calls `callback` when
* stopped, or an error occurs.
*
* @name whilst
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Function} test - synchronous truth test to perform before each
* execution of `iteratee`. Invoked with ().
* @param {Function} iteratee - 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 `iteratee` has stopped. `callback`
* will be passed an error and any arguments passed to the final `iteratee`'s
* callback. Invoked with (err, [results]);
* @returns undefined
* @example
*
* var count = 0;
* async.whilst(
* function() { return count < 5; },
* function(callback) {
* count++;
* setTimeout(function() {
* callback(null, count);
* }, 1000);
* },
* function (err, n) {
* // 5 seconds have passed, n = 5
* }
* );
*/
export default function whilst(test, iteratee, callback) {
callback = onlyOnce(callback || noop);
if (!test()) return callback(null);
var next = rest(function(err, args) {
if (err) return callback(err);
if (test()) return iteratee(next);
callback.apply(null, [null].concat(args));
});
iteratee(next);
}
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