Javascript jsx和map中的react if语句
我有工作代码,映射函数中的if语句有一个小问题Javascript jsx和map中的react if语句,javascript,reactjs,dictionary,Javascript,Reactjs,Dictionary,我有工作代码,映射函数中的if语句有一个小问题 const SortableItem = SortableElement(CashItem); const SortableList = SortableContainer(({items}) => { return ( <div> {items.map((cashitem, index) => ( <SortableItem key={`item-${index}`}
const SortableItem = SortableElement(CashItem);
const SortableList = SortableContainer(({items}) => {
return (
<div>
{items.map((cashitem, index) => (
<SortableItem key={`item-${index}`}
index={index}
isPayed={cashitem.isPayed}
date={cashitem.date}
name={cashitem.name}
realisticVal={cashitem.realisticVal}
realisticBalance={cashitem.realisticBalance}
optimisticBalance={cashitem.optimisticBalance}
optimisticVal={cashitem.optimisticVal}
changedName={(event) => this.nameChangedHandler(event, cashitem.id)}
isBlocked={(event) => this.handleChangeCheckbox(event, cashitem.id)}
delete={(event) => this.removeItem(event, cashitem.id)}
addNext={(event) => this.addNext(event, cashitem)}
realisticChange={(event) => this.realisticBalanceChangedHandler(event, cashitem.id)}
optimisticChange={(event) => this.optimisticBalanceChangedHandler(event, cashitem.id)}
dateChangedHandler={(event) => this.dateChangedHandler(event, cashitem.id)}
/>
))}
</div>
);
});
const SortableItem=SortableElement(现金项目);
const SortableList=SortableContainer(({items})=>{
返回(
{items.map((现金项目,索引)=>(
this.nameChangedHandler(事件,cashitem.id)}
isBlocked={(事件)=>this.handleChangeCheckbox(事件,cashitem.id)}
delete={(事件)=>this.removietem(事件,cashitem.id)}
addNext={(事件)=>this.addNext(事件,现金项目)}
realisticChange={(事件)=>this.realisticBalanceChangedHandler(事件,cashitem.id)}
optimisticChange={(事件)=>this.optimisticBalanceChangedHandler(事件,cashitem.id)}
dateChangedHandler={(事件)=>this.dateChangedHandler(事件,cashitem.id)}
/>
))}
);
});
现在我想要chceck if语句只在映射中cashitem has state为visible时呈现cashitems isVisible have isVisible:true或false我想这样做
const SortableItem = SortableElement(CashItem);
const SortableList = SortableContainer(({items}) => {
return (
<div>
{items.map((cashitem, index) => (
if(cashitem.isVisible===true){
<SortableItem key={`item-${index}`}
index={index}
isPayed={cashitem.isPayed}
date={cashitem.date}
name={cashitem.name}
realisticVal={cashitem.realisticVal}
realisticBalance={cashitem.realisticBalance}
optimisticBalance={cashitem.optimisticBalance}
optimisticVal={cashitem.optimisticVal}
changedName={(event) => this.nameChangedHandler(event, cashitem.id)}
isBlocked={(event) => this.handleChangeCheckbox(event, cashitem.id)}
delete={(event) => this.removeItem(event, cashitem.id)}
addNext={(event) => this.addNext(event, cashitem)}
realisticChange={(event) => this.realisticBalanceChangedHandler(event, cashitem.id)}
optimisticChange={(event) => this.optimisticBalanceChangedHandler(event, cashitem.id)}
dateChangedHandler={(event) => this.dateChangedHandler(event, cashitem.id)}
/>
}
))}
</div>
);
});
const SortableItem=SortableElement(现金项目);
const SortableList=SortableContainer(({items})=>{
返回(
{items.map((现金项目,索引)=>(
if(cashitem.isVisible==true){
this.nameChangedHandler(事件,cashitem.id)}
isBlocked={(事件)=>this.handleChangeCheckbox(事件,cashitem.id)}
delete={(事件)=>this.removietem(事件,cashitem.id)}
addNext={(事件)=>this.addNext(事件,现金项目)}
realisticChange={(事件)=>this.realisticBalanceChangedHandler(事件,cashitem.id)}
optimisticChange={(事件)=>this.optimisticBalanceChangedHandler(事件,cashitem.id)}
dateChangedHandler={(事件)=>this.dateChangedHandler(事件,cashitem.id)}
/>
}
))}
);
});
包含多个表达式的箭头函数需要:
- 它周围的支架
- 显式返回语句
(现金项目,索引)=>{
如果(条件){
返回
}
}
{
map((cashitem,index)=>{/您没有在if语句中返回组件
{items.map((cashitem, index) => {
if(cashitem.isVisible){
return <SortableItem key={`item-${index}`} ...otherProps/>
}
})}
{items.map((现金项目,索引)=>{
如果(cashitem.isVisible){
返回
}
})}
但是,既然您正在筛选列表,为什么不使用该方法呢
{items.filter(cashItem=>cashItem.isVisible).map((cashItem,index)=>(
)}
创建一个函数来处理if/else语句并返回jsx/html生成器,然后在jsx render()函数中调用它
检查/作者:
renderSkillSection:function(){
如果(this.state.challengeChoices.length<0){
返回this.state.challengeChoices.map((para2,i)=>
)
}
否则{
返回你好世界
}
},
render:function(){
返回(
{this.renderSkillSection()}
)
}
在地图功能中使用它?@PiotrBieszczad:如果您认为它回答了您的问题,请将其标记为答案,作为其他面临相同情况的人的参考
{
items.map((cashitem, index) => { //<== change it to curly braces
return cashitem.isVisible && (<SortableItem key={`item-${index}`} //<== using the return keyword
...
/>)
}
}
{items.map((cashitem, index) => {
if(cashitem.isVisible){
return <SortableItem key={`item-${index}`} ...otherProps/>
}
})}
{items.filter(cashItem => cashItem.isVisible).map((cashitem, index) => (
<SortableItem key={`item-${index}`} ...otherProps/>
)}
renderSkillSection: function(){
if (this.state.challengeChoices.length < 0) {
return this.state.challengeChoices.map((para2, i) =>
<ChallengeSkill key={i} {...para2} callback={this.madeSelection} />)
}
else {
return <div>Hello world</div>
}
},
render: function(){
return (<div className="skillSection">
{this.renderSkillSection()}
</div>)
}