异步 - 传递变量和保留上下文

Question

如果您有以下代码:

var asyncConfig = {};
var a, b;
for(var i = 0; i < someValue; i++) {
    // do something with a
    // do something with b
    asyncConfig[i] = function(callback) {
        func(a, b, callback); // func is async
    }
}
// Include some more parallel or series functions to asyncConfig
async.auto(asyncConfig);

• 你怎么能传递变量的值a,并b以 func这样当async.auto(asyncConfig)后执行for循环的背景下,a并b保留？

(不同上下文a和b用于每个执行func.)

先感谢您 !

Answer 1

var asyncConfig = {};
var a, b;
for(var i = 0; i < someValue; i++) {
    // do something with a
    // do something with b
    (function(a,b){
      asyncConfig[i] = function(callback) {
        func(a, b, callback); // func is async
      }
    })(a,b);
}
// Include some more parallel or series functions to asyncConfig
async.auto(asyncConfig);