76 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			76 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
var async = require('./async.js')
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  , abort = require('./abort.js')
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  ;
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// API
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module.exports = iterate;
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/**
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 * Iterates over each job object
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 *
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 * @param {array|object} list - array or object (named list) to iterate over
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 * @param {function} iterator - iterator to run
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 * @param {object} state - current job status
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 * @param {function} callback - invoked when all elements processed
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 */
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function iterate(list, iterator, state, callback)
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{
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  // store current index
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  var key = state['keyedList'] ? state['keyedList'][state.index] : state.index;
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  state.jobs[key] = runJob(iterator, key, list[key], function(error, output)
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  {
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    // don't repeat yourself
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    // skip secondary callbacks
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    if (!(key in state.jobs))
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    {
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      return;
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    }
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    // clean up jobs
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    delete state.jobs[key];
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    if (error)
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    {
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      // don't process rest of the results
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      // stop still active jobs
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      // and reset the list
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      abort(state);
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    }
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    else
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    {
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      state.results[key] = output;
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    }
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    // return salvaged results
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    callback(error, state.results);
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  });
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}
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/**
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 * Runs iterator over provided job element
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 *
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 * @param   {function} iterator - iterator to invoke
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 * @param   {string|number} key - key/index of the element in the list of jobs
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 * @param   {mixed} item - job description
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 * @param   {function} callback - invoked after iterator is done with the job
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 * @returns {function|mixed} - job abort function or something else
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 */
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function runJob(iterator, key, item, callback)
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{
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  var aborter;
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  // allow shortcut if iterator expects only two arguments
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  if (iterator.length == 2)
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  {
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    aborter = iterator(item, async(callback));
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  }
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  // otherwise go with full three arguments
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  else
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  {
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    aborter = iterator(item, key, async(callback));
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  }
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  return aborter;
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}
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