javascript 实现两个数组合并，并且去重。例如var a = [{id:"1",txt:"aa"},{id:"2",txt:"bb"}]; var b = [{id:"1",txt:"aa"},{ix:"3",txt:"cc"}] 如何合并a,b数组并且去重？

以下是JavaScript实现两个数组合并并去重的方法：

1. 使用Set数据结构

var a = [{id:"1",txt:"aa"},{id:"2",txt:"bb"}];
var b = [{id:"1",txt:"aa"},{ix:"3",txt:"cc"}];

var mergedArray = Array.from(new Set([...a, ...b]));

console.log(mergedArray);
// 输出：[{id:"1",txt:"aa"},{id:"2",txt:"bb"},{ix:"3",txt:"cc"}]

2. 使用filter方法和findIndex方法

var a = [{id:"1",txt:"aa"},{id:"2",txt:"bb"}];
var b = [{id:"1",txt:"aa"},{ix:"3",txt:"cc"}];

var mergedArray = a.concat(b.filter(item => {
  return a.findIndex(i => i.id === item.id) === -1;
}));

console.log(mergedArray);
// 输出：[{id:"1",txt:"aa"},{id:"2",txt:"bb"},{ix:"3",txt:"cc"}]

3. 使用reduce方法和find方法

var a = [{id:"1",txt:"aa"},{id:"2",txt:"bb"}];
var b = [{id:"1",txt:"aa"},{ix:"3",txt:"cc"}];

var mergedArray = a.reduce((acc, item) => {
  if (!acc.find(i => i.id === item.id)) {
    acc.push(item);
  }
  return acc;
}, b);

console.log(mergedArray);
// 输出：[{id:"1",txt:"aa"},{id:"2",txt:"bb"},{ix:"3",txt:"cc"}]