Javascript将集合代理到单个对象 [英] Javascript proxy a collection to single object

问题描述

我以前从未使用过Proxy，但是我认为应该可以将对象集合合并"到单个对象中. 它必须保持活动"状态，因为原始字段将对其执行值更改.

I've never used Proxy before, but I think it should be possible to "merge" an collection of objects into a single object. It needs to remain "live" because the original fields will have value changes performed on them.

在此阶段忽略按键碰撞:

Ignore key collisions at this stage:

给出:

const fields = [{
  name: 'hello',
  value: 1
 },{
   name: 'goodbye',
   value : 2
 }];

输出:

const proxy = { hello:1 , goodbye :2 }

我绝对需要能够使用for in遍历代理对象.

I definitely need to be able to iterate over the proxied object with a for in.

已在此处启动笔，但距离还很远: https://codepen.io/anon/pen/mMRaKw?editors=1111

Have start a pen here, but haven't got very far: https://codepen.io/anon/pen/mMRaKw?editors=1111

有可能吗?

推荐答案

我认为您正在寻找类似的东西:

I think you are looking for something like:

const fields = [{name: 'hello',value: 1}, { name: 'goodbye', value: 2}];

let handler = {
  get: function(target, name) {
    if (name === 'flatten') {    
      return target.reduce((a, c) => {
        a[c.name] = c.value;
        return a
      }, {});
    } else {
      return target[name];
    }
  },
   set: function(target, prop, value) {
      let obj = target.find(o => o.name === prop);
      if(obj) {        
         obj.value = value;
         return true;
      }
      return false;
      
   }
};

let prox = new Proxy(fields, handler);

console.log('flat obj', JSON.stringify(prox.flatten))

// update original
fields[0].value=10;
// change reflected in proxy
console.log('flatten.hello',prox.flatten.hello);
// update proxy
prox.goodbye = 200;
// change reflected in original
console.log('original', fields[1].value)

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