CODEWITHSUNDEEP
javascriptreactjsrandom
Abbas jafarnejad
Abbas jafarnejad

Reputation: 43

get a random item from a list of items with property by React js

i am trying to get a random item from a list. so far i managed to put my list in an array and i'm trying to get the item i need with a function but where i need it , it's undefined! i don't know where i am wrong!!!

i wanna see the result in this console log

 handleChange(event) {
    this.setState({value: event.target.value});
    var NewDictionary = this.Dictionary;
    console.log(Rand(NewDictionary));
  }

the whole code is here:

class Application extends React.Component{
  constructor(props) {
   super(props);
   this.state = {
     value:'option2',
     button:'submit',
   };
   this.Dictionary = {
     Salam:"Hi",
     khodafez:"Bye",
     are: "Yes",
     na: "No",
     shab: "Night",
     rooz: "Day",
   }
   this.handleChange = this.handleChange.bind(this);
   this.handleSubmit = this.handleSubmit.bind(this);
 }
 handleChange(event) {
    this.setState({value: event.target.value});
    var NewDictionary = this.Dictionary;
    console.log(Rand(NewDictionary));
  }
  handleSubmit(event) {
    this.setState({button: this.state.value});
    event.preventDefault();
  }

  render(){
    return(

  <form onSubmit={this.handleSubmit}>
  <div> {this.Dictionary.Salam}  </div>
  <div className="radio">
    <label>
      <input type="radio" value={this.Dictionary.Salam}
        checked={this.state.value === this.Dictionary.Salam}
        onChange={this.handleChange} />
        {this.Dictionary.Salam}
    </label>
  </div>
  <div className="radio">
    <label>
      <input type="radio" value="option2"
        checked={this.state.value === 'option2'}
        onChange={this.handleChange} />
      Option 2
    </label>
  </div>
  <div className="radio">
    <label>
      <input type="radio" value="option3"
        checked={this.state.value === 'option3'}
        onChange={this.handleChange} />
      Option 3
    </label>
  </div>
  <div className="radio">
    <label>
      <input type="radio" value="option4"
        checked={this.state.value === 'option4'}
        onChange={this.handleChange} />
        Option 4
    </label>
  </div>
  <button onClick={this.handleSubmit} className="btn btn-default" type="submit">{this.state.button}</button>
</form>

     )
   }
}
function Rand(NewDictionary){
  let i = NewDictionary.length - 1;
  const j = Math.floor(Math.random() * i);
  return NewDictionary[j];
}
ReactDOM.render(
  <Application />,
  document.getElementById('root')
);

Upvotes: 2

Views: 4553

Answers (1)

Chase DeAnda
Chase DeAnda

Reputation: 16441

It's because NewDictionary is an object and not an array, so trying to get an item by an index won't work. Instead, use Object.keys(NewDictionary) to create an array of keys, and then use the random index to get a random key.

function Rand(NewDictionary){
  const keys = Object.keys(NewDictionary);
  let i = keys.length - 1;
  const j = Math.floor(Math.random() * i);
  return NewDictionary[keys[j]];
}

Upvotes: 1

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