How do I pass a standard set of parameters to each function in an async.js series?

问题

Given the following node.js module, how would I call the functions in the array orderedListOfFunctions passing each one the response variable?

var async = require("async");
var one = require("./one.js");
var two = require("./two.js");

module.exports = function (options) {

var orderedListOfFunctions = [
    one,
    two
];

return function (request, response, next) {

    // This is where I'm a bit confused...
    async.series(orderedListOfFunctions, function (error, returns) {
        console.log(returns);
        next();
    });

};

回答1:

You can use bind to do this like so:

module.exports = function (options) {
  return function (request, response, next) {
    var orderedListOfFunctions = [
      one.bind(this, response),
      two.bind(this, response)
    ];

    async.series(orderedListOfFunctions, function (error, resultsArray) {
      console.log(resultArray);
      next();
    });
};

The bind call prepends response to the list of parameters provided to the one and two functions when called by async.series.

Note that I also moved the results and next() handling inside the callback as that's likely what you want.

回答2:

In keeping with OP's desire to do this without closing orderredListOfFunctions in the returned function:

var async = require("async");
var one = require("./one.js");
var two = require("./two.js");

module.exports = function (options) {

  var orderedListOfFunctions = function (response) {return [
      one.bind(this, response),
      two.bind(this, response)
   ];};

   return function (request, response, next) {
      async.series(orderedListOfFunctions(response), function (error, returns) {
         console.log(returns);
         next();
      });
   };
};

回答3:

Simple alternative is applyEachSeries -

applyEachSeries(tasks, args..., [callback])

Example -

function one(arg1, arg2, callback) {
    // Do something
    return callback();
}

function two(arg1, arg2, callback) {
    // Do something
    return callback();
}

async.applyEachSeries([one, two], 'argument 1', 'argument 2', function finalCallback(err) {
    // This will run after one and two
});

来源：https://stackoverflow.com/questions/14305843/how-do-i-pass-a-standard-set-of-parameters-to-each-function-in-an-async-js-serie

标签

node.js

middleware

async.js