Вы можете использовать обходной путь:
filterFeed = (value) => {//Pass the value, not the event
let searchString = value
let unfilteredFeed = this.unfilteredFeed;
let filteredFeed = unfilteredFeed.filter(el => el.title.toLowerCase().includes(value.toLowerCase()));
this.setState({
input: searchString,
feed: filteredFeed,
filter: true
})
}
И ваш JSX:
<input className="basic-slide" id="name" type="text" value={this.state.input} placeholder="Event..." onChange={(e)=>{
const value = e.target.value;
this.debouncedFilterFeed(value)
}} /><label >Suche</label>