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JavaScript React Components (2018) Managing State and Data Flow Controlled Components

Dom Ss
Dom Ss
4,339 Points
Posted by Dom Ss
Dom Ss
4,339 Points

What is being passed where in state/value?

So when I name differently value property, also the props from the form I still get an updated state object and no errors. For example, this does not give me any errors. Why?

`class AddPlayerForm extends Component {

state = {
    value2: ''
};

handleValueChange = (e) => {
    this.setState(
       { value2: e.target.value }
    ); 
}

render () {
    console.log(this.state.value2, 'value')
    return (
        <form> 
            <input
            type="text"
            value1={this.state.value3}
            onChange={this.handleValueChange}
            placeholder="Enter a player name"

            />
            <input 
            type="submit"
            value="Add Player"
            />

        </form>
    );
}

}`

1 Answer

Zimri Leijen
Zimri Leijen
11,772 Points

onChange={this.handleValueChange} will call the function handleValueChange when the text input is changed.

which will trigger this

this.setState(
       { value2: e.target.value }
    );

which sets the value2 key in the state to the value of the event that triggered it.

Dom Ss
Dom Ss
4,339 Points
Dom Ss
Dom Ss
4,339 Points

Thank you Zimri,

so "value3" from 

value1={this.state.value3}

does not have to match to "value2" from 

state = {
    value2: ''
};

?

Zimri Leijen
Zimri Leijen
11,772 Points

correct, I don't even think value1={this.state.value3} does anything at all