Question

如果'monkey'没有退出数组，写一个函数返回值true。

 const entities = [
           {
              id: 1,
              name: 'cat',
            },
            {
              id: 2,
              name: 'dog',
            },
            {
              id: 1,
              name: 'pig',
            },
    ];
const selection = 'monkey';

Answer 1

<强> ES6

entities.some((entity) => entity.name === selection);

<强> Lodash

_.some(entities, ['name', selection]);

Answer 2

这是一段示例代码。在函数中添加以下代码片段，调用它。它可以提供您想要的输出。

for(var i=0;i<entities.length;i++){
   if(entities[i].name == 'monkey')
      return true;
   else 
      continue;
}
return false;

Answer 3

考虑到你的数组将包含你提到的对象，你可以做这样的事情

private function _inArray(arr, value, key = "name"): boolean {
    let found: boolean = false;
    arr.some((obj) => {
       return (found = obj[key] == value);
    });
    return found;
}
...
...
myFunc() {
    const entities = [
       {
          id: 1,
          name: 'cat',
        },
        {
          id: 2,
          name: 'dog',
        },
        {
          id: 1,
          name: 'pig',
        },
    ];
    const selection = 'monkey';
    this._inArray(entities, selection);
    //Since you need it in lodash here it is
    _.some(entities, ['name', 'monkey']);
}

Answer 4

这是一个es2015解决方案。

  const entities = [
{
    id: 1,
    name: 'cat',
},
{
    id: 2,
    name: 'dog',
},
{
    id: 1,
    name: 'pig',
},
];


function doesntContainMonkey() {
    return !entities.find(x=>x.name === 'monkey');
}

doesntContainMonkey(); //true

Answer 5

function searchInArray(s, a, prop) {

    for(var i = 0; i < a.length; i++) {

        if(a[i][prop] === s) return i;

    }

    return false;

}

用法：

searchInArray("monkey", entities, "name")

Answer 6

试试这种方式

var index=entities.findIndex(x=>x.name==selection);

if(index == -1)//-1 means the searched item is not present.
  return true;
else
  return false;

如何在具有嵌套对象的项目数组中查找值是否存在

6 个答案: