非同期と next()

next.js

log = console.log.bind(console);
var assert = require('assert');

function test() {
  var tests = Array.prototype.slice.call(arguments);
  function next() {
    if(!tests.length) return;
    var args = Array.prototype.slice.call(arguments);
    args.push(next);
    var t = tests.shift();
    t.apply(null, args);
  };
  next();
};


test(function(next) {
  var a = 0;
  a ++; log(a);
  assert.equal(a, 1);
  next(a, 1);
}, function(a, b, next) {
  setTimeout(function() {
    a += b; log(a);
    assert.equal(a, 2);
    next(a);
  }, 200);
}, function(a, next) {
  setTimeout(function() {
    a ++; log(a);
    assert.equal(a, 3);
    next();
  }, 100);
});