javascript - 从函数返回 JSX

Question

我有一个组件需要检查多个选项并根据这些选项返回。因此，我创建了一个在我的组件返回语句中调用的外部函数，以确定将返回的格式:

render() {
    const { policy } = this.props;
    let deployment = policy.Deployment;
    let value = policy.value;
    let policyLegend = deployment.policyLegend;
    let policyObj = this.valueToPolicy(policyLegend, value);
    console.log(policyObj);
    if(policy.name == "SP4") {
      policyLegend[1].values = this.formatSp4Firmware(policyLegend[1]);
      return (
        <div>
          <Form onSubmit={ (event) => this.handleSubmit(event, this.props) }>
            {
              policyLegend.map((policy) => {
                return (
                  <div key={ policy.id }>
                    <h3>{ policy.displayName }</h3>
                    { this.renderSp4Policies(policy) }
                  </div>
                );
              })
            }
            <Button name={ 'Submit' } type='submit'>Submit</Button>
            <Button onClick={ this.props.onCancel }>Cancel</Button>
          </Form>
        </div>
      )
    } 
  }

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>

renderSp4Policies(policy) {
    if(policy.displayName == "Firmware Options") {
      let firmwareDropdownNames = this.formatFirmawareDropdownNames(policy);
      let toggles = policy.values[0][Object.keys(policy.values[0])];
      let toggleOptions = []
      Object.keys(toggles).map(toggle => {
      	if(typeof(toggles[toggle]) == "boolean"){
          var obj = {};
          obj[toggle] = toggles[toggle];
      		toggleOptions.push(obj);
        }
      })
      return (
        toggleOptions.map(toggleOption => {
          let toggleName = Object.keys(toggleOption).toString();
          return (
            <Form.Field key={ toggleName }>
              <label>{ toggleName }</label>
              <Checkbox toggle />
            </Form.Field>
          )
        })
      )
    } else {
        return (
          policy.values.map(value => {
            return(
              <Form.Field key={ value.name }>
                <label>{ value.displayName || value.name }</label>
                <Checkbox toggle />
              </Form.Field>
            )
          }
        )
      )
    }
  }

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>

编辑

我已经应用了一些给出的答案并取得了一定的成功。

在 renderSp4Policies 中，显示 else 语句中返回的内容，但开头 if(policy.displayName == "Firmware Options") 什么都不返回。

感谢所有建议，提前致谢!

Answer 1

您的 map 函数不返回任何内容:

policy.values.map(value => {
            <Form.Field key={ value.name }>
              <label>{ value.displayName || value.name }</label>
              <Checkbox toggle />
            </Form.Field>
          } 

使用箭头功能 block {} 时，您应该添加显式的 return 语句:

policy.values.map(value => {
            return(<Form.Field key={ value.name }>
              <label>{ value.displayName || value.name }</label>
              <Checkbox toggle />
            </Form.Field>)
          }

编辑
作为您评论的后续。

至于第一个if语句，不要使用forEach，使用map。与您在第二个 if 语句中所做的相同(不要忘记 return!)

renderSp4Policies(policy) {
  if (policy.displayName == "Firmware Options") {
    let toggles = policy.values[0][Object.keys(policy.values[0])];
    Object.keys(toggles).forEach(toggle => {
      if (typeof (toggles[toggle]) !== "boolean") {
        delete toggles[toggle];
      }
    })
    return (
      Object.keys(toggles).map(toggle => {
        return (
          <Form.Field key={toggle}>
            <label> {toggle} </label>
            <Checkbox toggle />
          </Form.Field>
        );
      })
    )
  } else {
    return (
      policy.values.map(value => {
        <Form.Field key={value.name}>
          <label>{value.displayName || value.name}</label>
          <Checkbox toggle />
        </Form.Field>
      })
    );
  }
}