手写用 ES6proxy 如何实现 arr[-1] 的访问（滴滴2020）

[Sunny-117]

[CXGBro]

let arr= [1,2,3,4]
let proxy = new Proxy(arr,{
  get(target,key){
    if(key<0){
      return target[target.length+parseInt(key)]
    }
    return target[key] 
  }
})
console.log(proxy[-2]);
console.log(proxy[2]);

[cscty]

        let a = [1, 2, 3];
        let proxy = new Proxy(a, {
            get(target, key) {
                if (key === "-1") {
                    return target[target.length - 1];
                }
            },
        });
        console.log(proxy[-1]);

[mafeiGitHub]

let arr = [1, 2, 3, 4]
let proxy = new Proxy(arr, {
    get(target, key) {
        if (key < 0) {
            return target[target.length + parseInt(key)]
        }
        return target[key]
    }
})
// 测试
console.log(proxy[-1]);

[dizao006]

let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];

function observe(arr) {
  const proxy = new Proxy(arr, {
    get(target, key) {
      let v = target[key];
      if (typeof v === "object") {
        observe(v);
      }
      if (key < 0) {
        let len = target.length;
        key = len - -key;
      }
      return target[key];
    },
  });
  return proxy;
}

const arr2 = observe(arr);
console.log(arr2[-4]);

[Windseek]

const arrProxy = (arr, index) => {
  let proxy = new Proxy(arr, {
    get: (target, key) => {
      if(key < 0) {
        return target[target.length - key*-1];
      }
      return target[key];
    }
  })

  return proxy[index];
}

var a = [1, 2, 3, 4, 5];
console.log(arrProxy(a, -1));