TS - 如何从新旧数组中获取数组中已删除和添加的项？

Question

假设我们有这个

oldArray = [
    { id: 1, position: 'DEV OM'},
    { id: 2, position: 'Senior Developer'},
]

newArray = [
    { id: 2, position: 'Senior Developer'},
    { id: 3, position: 'Junior Developer'},
]

现在我们如何才能在这些数组中获取已删除和添加的项目？

addedItems = getAddedItems(oldArray, newArray)
removedItems = getRemovedItems(oldArray, newArray)


// Output for addedItems
[
    { id: 3, position: 'Junior Developer'}
]

// Output for removedItems
[
    { id: 1, position: 'DEV OM'}
]

我正在使用typescript / angular2 app

Answer 1

您需要的是找到2个数组之间差异的函数：

＆＃13;

＆＃13;

let oldArray = [
    { id: 1, position: 'DEV OM'},
    { id: 2, position: 'Senior Developer'}
]

let newArray = [
    { id: 2, position: 'Senior Developer'},
    { id: 3, position: 'Junior Developer'}
]

function difference(a,b) {
  return a.filter(itema => !b.some(itemb => itemb.id===itema.id));
}

console.log(difference(oldArray,newArray))
console.log(difference(newArray,oldArray))

＆＃13;

＆＃13;

＆＃13;