我如何在localStorage中分配localForage中的变量？ [英] How do I assign a variable from localForage as I do in localStorage?

问题描述

请帮我解决以下问题。

Please help me with the following.

我一直在将我的AngularJS应用程序从localStorage转换为localForage。

I have been converting my AngularJS application from localStorage to localForage.

在我的应用程序中我分配了localStorage像这样的价值。

throughout my application I was assigning the localStorage value like this.

window.localStorage.setItem('localSavedValue','SavedValue');

然后我正在检索这样的数据，

and then I was retrieving the data like this,

var myValue = window.localStorage.getItem('localSavedValue');

所以当我在console.log（myValue）时; //输出'SavedValue'

So when I console.log(myValue); // it outputted 'SavedValue'

我尝试使用localForage时似乎无法做到这一点，

I cannot seem to do this with localForage when I try,

$localForage.setItem('localSavedValue','SavedValue');
var myValue = $localForage.getItem('localSavedValue');
console.log(myValue); // returns an object.

我没有将值设置为myValue。

I don't get the value set to myValue.

我确信这是与promises有关的事情，因为当我使用回调时我可以访问正确的'myValue'但是我想把它从调用中取出来用于其余的服务。

I am sure this is something do do with promises as when I use the callback I can access the correct 'myValue' however I want to get it out of the call back to use in the rest of the service.

另外要注意，我在服务中因此无法分配到$ scope（除非我不知道如何）。

Also to note, I am in a service so can't assign to $scope (unless I don't know how).

感谢任何帮助。

谢谢
B

推荐答案

LocalForage在设计上是异步的，所以我建议你使用像@RouR建议的Promise。

LocalForage is async by design so I would suggest you to use Promises like @RouR suggested.

代码清晰度的一个小改进是链 - 返回promise结果，但你仍然无法避免异步代码的后果。

A minor improvement for code clarity would be to chain-return the promise results, but you still can't avoid the async code consequences.

$localForage.setItem('localSavedValue','SavedValue').then(function() {
    return $localForage.getItem('localSavedValue');
}).then(function(data) {
    console.log('I\'m printed second', data); 
});
console.log('I\'m printed first'); 

如果您使用的是Babel，这种迁移的更友好方法是将其配置为使用< a href =https://babeljs.io/docs/plugins/transform-async-to-generator/\"rel =nofollow noreferrer> transform-async-to-generator 或 preset-es2017 并重写代码为

If you are using Babel, a more friendly approach for such migrations would be to configure it to use transform-async-to-generator or preset-es2017 and rewrite such code as

await $localForage.setItem('localSavedValue','SavedValue');
const data = await $localForage.getItem('localSavedValue');
console.log(data);

这篇关于我如何在localStorage中分配localForage中的变量？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！