检查作为对象属性的数组中是否存在元素

Question

我正在使用 Lodash，我想检查一个元素是否存在于一个数组中，该元素实际上是一个对象的属性（在我的例子中是“特征”），它本身就是数组的一部分。我尝试了 _.some 和 _.find 但我没有成功

const element = 'Hello'
class Example {
    constructor {}

  async featuresCheck () {
    this.Array = [
      { name: something
       surname: somethingelse
       features:[element, ...]
     }, 
    ]

    if (_.some(this.Array,{features:element})){
      console.log('element included')
    } else {
      console.log('element not included')
    }
  } 

}

Answer 1

Ori 的回答是正确的。这是一个使用lodash.some 的附加示例。

const element = 'Hello';

const array = [{
  name: 'foo',
  features: [element, 'bar']
}, {
  name: 'baz',
  features: []
}];

const doesFeatureExist = (requiredFeature) => _.some(array, (object) => _.some(object.features, (feature) => feature === requiredFeature));

console.log(doesFeatureExist(element));
console.log(doesFeatureExist('bar'));
console.log(doesFeatureExist('foo'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>

更新： 以下是使用 JS 类实现所需结果的方法：

const element = 'Hello'

class Example {
  constructor() {
    this.array = [{
      name: 'foo',
      features: [element, 'bar']
    }, {
      name: 'baz',
      features: []
    }];
  }

  featuresCheck(requiredFeature) {
    if (_.some(this.array, (object) => _.some(object.features, (feature) => feature === requiredFeature))) {
      console.log('element included')
    } else {
      console.log('element not included')
    }

  }
}

const example = new Example();

example.featuresCheck(element);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>

Answer 2

要检查是否存在，请使用嵌套的Array.some()（或_.some()）调用。要查找对象，请使用 Array.find() 和 Array.some()：

const element = 'Hello'

const arr = [
 { features:['not hello'] }, 
 { features:['Hello'] }, 
]

const exists = arr.some(o => o.features.some(el => el === element))
const item = arr.find(o => o.features.some(el => el === element))

console.log('exists: ', exists)
console.log('item: ', item)