I'm wanting to convert this class component into a handleChange
event that works in a function component. I'm not entirely sure that's possible, it may have to be a hook. I can't quite get the syntax right.
class CheckboxForm extends Component {
constructor(props) {
super(props);
this.state = { value: [] };
this.handleChange = this.handleChange.bind(this);
}
handleChange(event) {
const input = event.target.value;
this.setState(
{
value: this.state.value.includes(input)
? this.state.value.filter((item) => item !== input)
: [...this.state.value, input],
},
() => {
console.log("CheckBox: ", this.state.value);
}
);
}
My attempt:
export const CheckboxHook = (props) => {
const [value, setValue] = useState([]);
const handleCheckbox = (event) => {
const input = event.target.value;
setValue(
value.include(input)
? value.filter((item) => item !== input)
: [value, input],
() => {
console.log("Checkbox: ", value);
}
);
};
};
Seems like you're trying to do something like this? You don't need any custom hooks for it - just useState
and useEffect
.
const CheckboxForm = (props) => {
const [checkedItems, setCheckedItems] = useState([]);
useEffect(() => {
// equivalent to passing a callback to `this.setState` in class component
console.log("Checked: ", checkedItems);
}, [checkedItems])
const handleCheckbox = (event) => {
const { value } = event.target;
// setting with hooks must use a callback
// if you need access to the previous value
setCheckedItems(items =>
items.includes(value)
? items.filter(item => item !== value)
: [...items, value]
);
};
return <form>
<label>a <input value="a" type="checkbox" onChange={handleCheckbox} /></label>
<label>b <input value="b" type="checkbox" onChange={handleCheckbox} /></label>
<label>c <input value="c" type="checkbox" onChange={handleCheckbox} /></label>
</form>
};