Reactjs eslint：Missing "key" prop for element in iterator (reactjsxkey)

我是新手，我正在try 输出一个包含用户信息的表.但Eslint一直在给我以下错误:

[eslint] Missing "key" prop for element in iterator [react/jsx-key]

我不确定我是否正确地做到了这一点，但我已经为用户列表中的每个人分配了一个唯一的ID号，但不确定为什么错误会持续存在.

所以在我的名片上.我有以下几点:

import React from "react";
import {
  Card,
  CardImg,
  CardText,
  CardBody,
  CardTitle,
  CardSubtitle,
  Button
} from "reactstrap";
import PropTypes from "prop-types";

class PeopleCard extends React.Component {
  static propTypes = {
    person: PropTypes.object,
    id: PropTypes.number,
    name: PropTypes.string,
    company: PropTypes.string,
    description: PropTypes.string
  };
  render() {
    return (
      <div>
        <Card>
          <CardImg
            top
            width="100%"
            src="https://via.placeholder.com/318x180.png"
            alt="Card image cap"
          />
          <CardBody>
            <CardTitle>{this.props.person.name}</CardTitle>
            <CardSubtitle>{this.props.person.company}</CardSubtitle>
            <CardText>{this.props.person.description}</CardText>
            <Button>Button</Button>
          </CardBody>
        </Card>
      </div>
    );
  }
}

export default PeopleCard;

在我的主要区域.js，我有以下几点:

import React from "react";
import { Container, Row, Col } from "reactstrap";
import PeopleCard from "./PeopleCard";

class MainArea extends React.Component {
  constructor() {
    super();
    this.state = {
      people: [
        {
          id: 1,
          name: "John",
          company: "Some Company, Inc",
          description: "Met at a party."
        },
        {
          id: 2,
          name: "Mary",
          company: "Some Company, Inc",
          description: "Met at a party."
        },
        {
          id: 3,
          name: "Jane",
          company: "Some Company, Inc",
          description: "Met at a party."
        }
      ]
    };
  }
  render() {
    let peopleCard = this.state.people.map(person => {
      return (
        <Col sm="4">
          <PeopleCard key={person.id} person={person} />
        </Col>
      );
    });
    return (
      <Container fluid>
        <Row>{peopleCard}</Row>
      </Container>
    );
  }
}

export default MainArea;

下面的一行抛出了错误，我不知道为什么:

<Col sm="4">
   <PeopleCard key={person.id} person={person} />
</Col>

如何防止出现此错误？