比较数组的每个元素以进行反应状态

Question

嗨，我不知道如何将数组的每个元素与状态进行比较：

doesCustomerExist = () => {
  const { customers } = this.props;
  let result = customers.map(c => c.phone)
  if(result === this.state.phone)
    return (console.log('already exist'))
    console.log(result)
}

Answer 1

您可以使用indexOf检查数组是否包含给定元素。

例如：

const phone = "123";
const customers = ["111", "222", "333", "123"];

const isInArray = customers.indexOf(phone) > -1;

console.log(isInArray);

Answer 2

为此，只需使用Array.inlcudes：

const phone = "123";
const customers = ["111", "222", "333", "123"];

const isFound = customers.includes(phone)

console.log(isFound);