在不使用lodash的情况下合并两个数组的条件

Question

我面临着合并两个数组的问题.我有两个对象数组首先是prev值有旧值而另一个有更新值.我希望结果数组包含prev数组的所有对象,其中数组的更新值接下来,并且在下一个数组中也有对象.

例:

var prev = [{id: 1, val: 'abc'}, {id: 2, val: 'pqr'}];
var next = [{id: 1, val: 'nextVal'}, {id: 3, val: 'xyz'}];

预期

mergeOutput = [
  {id: 1, val: 'nextVal'}, // value is updated 
  {id: 2, val: 'pqr'}, 
  {id: 3, val: 'xyz'}
]

注意:数组顺序无关紧要.

Answer 1

您可以使用Map()合并数组.

var prev = [{id: 1, val: 'abc'}, {id: 2, val: 'pqr'}];
var next = [{id: 1, val: 'nextVal'}, {id: 3, val: 'xyz'}];

var hash = new Map();
prev.concat(next).forEach(function(obj) {
    hash.set(obj.id, Object.assign(hash.get(obj.id) || {}, obj))
});

var mergedArray = Array.from(hash.values());
console.log(mergedArray);

来源:StackOverflow