首页 > 解决方案 > JavaScript如何从地图数组中获取长度

问题描述

我是 JSX 的新手,我正在尝试获取每个团队this.state.teams[0].employee.length的员工数量,这会给我[0]数组中对象的员工数量,我怎样才能获得每个团队的员工数量并且只渲染一次?

render() {
    const {teams, isLoading} = this.state;
    const { location } = this.props;

    if (isLoading) {
        return <p>Loading...</p>;
    }
    // console.log("Number of Employees team", this.state.teams[0].employee.length);
    

    const teamList = teams.map(team => {

        console.log("TEAM Employees", teams[0].employee.length);

        return <tr key={team.id}>
               <td>
                <div className="tableContent">
                    <div>
                         {team.name} 
                    </div>
                    <div>
                      <ul>{team.employee.map(employee => {
                       return <li key={employee.id}>{employee.name}: {employee.email}</li>
                      })}</ul>
                    </div>
                    <div>
                     {team.employee.map(employee => {
                       return <li key={employee.id}>{teams[0].employee.length}</li>
                      })}
                    </div>
                </div>                    
            </td>
        </tr>
    });

标签: javascriptreactjsjsx

解决方案


您可以为特定团队尝试此操作:

const teamList = teams.map(team => {
   console.log("TEAM Employees", team.employee.length);
}

或所有团队中的员工人数:

const numberOfAllEmployees = teams.map(team => team.employee.length).reduce((a,b) => a + b);

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