Javascript代码执行顺序异常

Javascript code execution order strangeness(Javascript代码执行顺序异常)

问题描述

我有一段 Javascript/Coffeescript 似乎执行不正常.

I have a section of Javascript/Coffeescript that seems to be executing out of order.

console.log list
console.log list[card_number]
if list[card_number]
  console.log "MATCHES"
  new_card = list[card_number]
else
  console.log "NO MATCHES"
  new_card = create_new_card(card_number)

create_new_card: (card_number) ->
  new_card =
    card_number: card_number
  list[new_card.card_number] = new_card
  return new_card

每次运行时，第一个 console.log 都会显示包含 new_card 的卡片列表，即使卡片尚未创建.然后它总是点击 else，不管它运行多少次.

Every time I run this, the first console.log shows a list of cards that includes the new_card, Even if the card hasn't been created yet. Then it ALWAYS hits the else, no matter how many times it is run.

如果我在这段代码运行后尝试在 Javascript 控制台中运行 list[<card_number>]，我会收到正确的对象，但每次代码自行运行时，都会出现相同的事件发生.

If I attempt to run list[<card_number>] in the Javascript console after this code runs, I receive the proper object, but each time the code runs on it's own, the same event happens.

推荐答案

在 google chrome 中，如果你想用它们在记录时的状态记录对象，你需要记录一个克隆对象或者只是将它字符串化.

In google chrome, if you want to log objects with the state they had at the time of logging, you need to log a clone object or just stringify it.

var a = [];
console.log(a);
a[0] = 3;

将记录 [3] 因为它记录了一个活动对象，而这将记录 []:

Will log [3] because it logs a live object, while this will log []:

var a = [];
console.log(JSON.parse(JSON.stringify(a)));
a[0] = 3;

它也是一个活动对象日志记录，但它是在 a 没有任何项目的时间点克隆的一次性克隆.

It is also a live object logging but it is a throwaway clone that was cloned at the point in time when a didn't have any items.

这与@CallumRogers 指出的代码中可能存在的逻辑错误无关.

This is not related to the possible logical errors in your code that @CallumRogers pointed out.

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