检查元素是否存在于作为对象属性的数组中

Question

我正在使用 Lodash，我想检查一个元素是否存在于数组中，该元素实际上是一个对象的属性（在我的例子中是“特征”），该对象本身是数组的一部分。 我尝试使用 _.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

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)

Answer 2

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>