【async.waterfall】
if any of the tasks pass an error to their own callback, the next function is not executed, and the main callback is immediately called with the error.
async.waterfall([
function(callback) {
callback(null, 'one', 'two');
},
function(arg1, arg2, callback) {
// arg1 now equals 'one' and arg2 now equals 'two'
callback(null, 'three');
},
function(arg1, callback) {
// arg1 now equals 'three'
callback(null, 'done');
}
], function (err, result) {
// result now equals 'done'
});
// Or, with named functions:
async.waterfall([
myFirstFunction,
mySecondFunction,
myLastFunction,
], function (err, result) {
// result now equals 'done'
});
function myFirstFunction(callback) {
callback(null, 'one', 'two');
}
function mySecondFunction(arg1, arg2, callback) {
// arg1 now equals 'one' and arg2 now equals 'two'
callback(null, 'three');
}
function myLastFunction(arg1, callback) {
// arg1 now equals 'three'
callback(null, 'done');
}