在Javascript中修改数组值

Question

我有以下Javascript，我试图在其中修改数组中属性的单个字段。数组itenm可能有任意数量的字段，但模板将只指定rowId (用于标识该项)和新属性值。

代码如下：

​

function findRow(rowId) {
    return this.seniorityList.find(element => element.rowId==rowId);
}

this.seniorityList = [
    {Seniority:0, Rate:1.1, rowId:'row-0'},
    {Seniority:6, Rate:1.3, rowId:'row-1'},
    {Seniority:12, Rate:1.6, rowId:'row-2'},
    {Seniority:18, Rate:1.9, rowId:'row-3'},
    {Seniority:24, Rate:2.1, rowId:'row-4'}
];
let template = {Rate:99.99, rowId:'row-2'}

let row = findRow('row-2');

row = {...row, ...template };

console.log('array '+JSON.stringify(this.seniorityList));

​

我更希望输出会显示Rate的更新值，但实际上，它显示的是原始值。如果我对单个行执行console.log，那么它会正确地显示更改，但数组本身没有变化。如何更新数组？

Answer 1

{...row, ...template }创建一个新的实例，您可以使用Object.assign覆盖内容(或手动分配)。

​

function findRow(rowId) {
    return seniorityList.find(element => element.rowId==rowId);
}

let seniorityList = [
    {Seniority:0, Rate:1.1, rowId:'row-0'},
    {Seniority:6, Rate:1.3, rowId:'row-1'},
    {Seniority:12, Rate:1.6, rowId:'row-2'},
    {Seniority:18, Rate:1.9, rowId:'row-3'},
    {Seniority:24, Rate:2.1, rowId:'row-4'}
];
let template = {Rate:99.99, rowId:'row-2'}

let row = findRow('row-2');

//or row.Rate = template.Rate
Object.assign(row,template)

console.log('array '+JSON.stringify(seniorityList));

​

Answer 2

由于您的数组中实际上有一个对象，因此可以使用以下属性：

​

function findRow(rowId) {
  return this.seniorityList.find(element => element.rowId == rowId);
}

this.seniorityList = [{
    Seniority: 0,
    Rate: 1.1,
    rowId: 'row-0'
  },
  {
    Seniority: 6,
    Rate: 1.3,
    rowId: 'row-1'
  },
  {
    Seniority: 12,
    Rate: 1.6,
    rowId: 'row-2'
  },
  {
    Seniority: 18,
    Rate: 1.9,
    rowId: 'row-3'
  },
  {
    Seniority: 24,
    Rate: 2.1,
    rowId: 'row-4'
  }
];
let template = {
  Rate: 99.99,
  rowId: 'row-2'
}

let row = findRow('row-2');

row.Rate = 99.99;

console.log('array' + JSON.stringify(this.seniorityList))

​