多个受控文本输入反应缓慢

Question

我有一个包含多个文本输入的表单.我将它们全部设置为受控输入.键入时,新文本在字段中显示的延迟最多可达数秒.这是一个示例字段:

<label>Event Name</label>
<input type="text" 
       placeholder="Title"
       className="form-control"
       name="title"
       value={this.state.event.title}
       onChange={this.handleChange} />

我无法弄清楚是什么导致它如此缓慢或如何解决它.

更新:这是组件,应该足以显示正在发生的事情.

let CreateEventForm = React.createClass({
  submit: function () {},
  handleChange: function(e){
    let value = e.target.value;
    let name = e.target.name;
    if(value === 'true'){
      value = true;
    }
    if(value === 'false'){
      value = false;
    }
    // If true/false toggle old
    let oldState = this.state.event[name];
    if(typeof oldState === 'boolean'){
      value = !oldState;
    }
    // If is array
    if(name.indexOf('[]') > -1){
      name = name.replace('[]', '');
      oldState = this.state.event[name];
      var pos = oldState.indexOf(value);
      if(pos > -1){
        oldState.splice(pos, 1);
      } else {
        oldState.push(value);
      }
      value = oldState;
    }
    let event = this.state.event;
    event[name] = value;
    this.setState({event: event});
    console.log(this.state.event);
  },
  getClasses(field, additionalClasses = []) {
    // If a string is passed for additional class, make array
    if(!Array.isArray(additionalClasses)){
      additionalClasses = [additionalClasses];
    }
    let useDefaultColumns = additionalClasses.filter(function(className){
        return className.indexOf('col-') > -1;
      }).length === 0;
    let hasError = function(){
      let fields = Array.isArray(field) ? field : [field];
      return fields.filter(function(field){
          return !this.props.isValid(field);
        }.bind(this)).length > 0;
    }.bind(this)();
    return classnames({
      'col-sm-4': useDefaultColumns,
      'form-group': true,
      'has-error': hasError
    }, additionalClasses);
  },
  render: function () {
    return (
      <form ref="eventForm" onSubmit={this.submit}>
        <SavedModal isOpen={this.state.saved} reset={this.resetForm} style={this.state.modals.styles} />
        <h3>Info</h3>

        <div className="row">
          <div className={this.getClasses('title')}>
            <label>Event Name</label>
            <input type="text" placeholder="Title"
                   className="form-control"
                   name="title"
                   value={this.state.event.title}
                   onChange={this.handleChange} />
            {this.renderHelpText(this.props.getValidationMessages('title'))}
          </div>
        </div>
        <div className="row">
          <div className={this.getClasses('type')}>
            <label>Event Type</label>
            <select name="type"
                    className="form-control"
                    value={this.state.event.type}
                    onChange={this.handleChange}
                    onBlur={this.props.handleValidation('type')}>
              <option value="">Select Event Type&hellip;</option>
              {this.state.calendarTypes.map(function (type, key) {
                return <option value={type.name} key={key}>{type.name}</option>
              })}
            </select>
            {this.renderHelpText(this.props.getValidationMessages('type'))}
          </div>
        </div>

        <h3>Duration</h3>

        <div className="row">
          <div className="form-group col-sm-2">
            <input type="checkbox" name="allDay" checked={this.state.event.allDay} onChange={this.handleChange}/> All Day
          </div>
        </div>
        <div className="row">
          <div className="form-group col-sm-2">
            <input type="checkbox" name="repeats" checked={this.state.event.repeats} onChange={this.handleChange}/> Repeats&hellip;
          </div>
          <br/><br/>
        </div>

        <h3>Location</h3>
        <div className="row">
          <div className={this.getClasses('location')}>
            <select name="location"
                    className="form-control"
                    value={this.state.event.location}
                    onBlur={this.props.handleValidation('location')}
                    onChange={this.handleChange}>
              <option value="">Select a Location&hellip;</option>
              {this.state.locations.map(function (location, key) {
                return (
                  <option value={location.name} key={key}>{location.name}</option>
                );
              })}
            </select>
            {this.renderHelpText(this.props.getValidationMessages('location'))}
          </div>
        </div>

        <h3>Description</h3>
        <div className="row">
          <div className={this.getClasses('description')}>
            <label>Write a description:</label>
            <textarea className="form-control"
                      name="description"
                      value={this.state.event.description}
                      onChange={this.handleChange}
                      onBlur={this.props.handleValidation('description')}
                      rows="10"></textarea>
            {this.renderHelpText(this.props.getValidationMessages('description'))}
          </div>
        </div>

        <h3>Event Details</h3>
        <div className="row">
          <div className={this.getClasses('fee')}>
            <label>Fee:</label>
            <input type="text"
                   className="form-control"
                   name="fee"
                   value={this.state.event.fee}
                   onChange={this.handleChange}
                   onBlur={this.props.handleValidation('fee')}/>
            {this.renderHelpText(this.props.getValidationMessages('fee'))}
          </div>
        </div>

        <div className="row">
          <div className="col-sm-12">
            <button className="btn btn-primary" type="submit">
              Create Event
            </button>
          </div>
        </div>

      </form>
    );
  }
});

Answer 1

我有类似的情况,我的解决方案是禁用React Dev Tools.它们以某种方式影响输入字段.问题是如果您单击了React Dev Tools选项卡,则刷新页面是不够的.它们仍在影响您的投入.您必须打开新页面才能阻止它们.您也可以完全从Chrome中删除它们,但我不建议这样做,因为它们很有用.:)

Answer 2

造成这种情况的原因有很多种.我遇到了类似的问题并将主要原因过滤到:

• 大状态,所以它需要一段时间
• React Dev Tool /使用非缩小反应
• 变异状态数据

不管是什么原因,我找到了一个快速解决方案.如果您只想将其存储到状态但不使用它进行实时渲染.然后你可以安全地将'onChange'替换为'onBlur'.这没有dealay和滞后.如果您知道任何其他情况不起作用,请告诉我!

更改代码如下:

<label>Event Name</label>
<input 
   type="text" 
   placeholder="Title"
   className="form-control"
   name="title"
   value={this.state.event.title}
   onBlur={this.handleChange} />

Answer 3

看到这仍然得到回应，我想我会更新它并关闭它。调用handleChange内部onChange会导致整个表单在每次更改时重新呈现，从而减慢速度。如果您有一个简单的表单，您可以只更新onBlur或创建单独的输入组件，以便重新渲染将与该一个输入隔离。就我个人而言，我使用并且推荐使用Formik来构建表单，因为它为您抽象了这种复杂性。