Array.map一次渲染相同的标题

时间:2020-06-03 19:58:18

标签: javascript reactjs arraylist array-map

我有密码数组,我想显示这些密码-每个密码都有一个资源,应该作为标题显示一次 所以: 以资源为标题:

资源1:-密码1-密码2-密码0

资源2:-密码4-密码5,

资源3:-密码6-密码7-密码8-密码9

        this.state.passwords && this.state.passwords.map((item, index) => {
            return (
                <>
                    {item[index] !== item[index + 1] && (  //here I am trying to do this logic
                        <Nav.Item><div className="sidebar-heading-secrets">{item.resource}</div></Nav.Item>
                    )}
                    <span>We render data here</span>
                </>
            )
        })
    }``

1 个答案:

答案 0 :(得分:0)

您缺少地图中的钥匙。使用React.Fragment并提供密钥

this.state.passwords && this.state.passwords.map((item, index) => {
            return (
                <React.Fragment key={index}>
                    {item[index] !== item[index + 1] && (  //here I am trying to do this logic
                        <Nav.Item><div className="sidebar-heading-secrets">{item.resource}</div></Nav.Item>
                    )}
                    <span>We render data here</span>
                </React.Fragment>
            )
        })
    }``