Cfrgtkky

Is there anyway that I could check if a number already exists (and for instance, if there are more than one instance of a particular number, etc) in state with this code? I can´t figure out any, and I´ve tried all methods I could think of (Indexof, contains, etc, even turning value into an array didn´t help).

const button1 = [{number: 'one', value: '1'},{number: 'two', value: '2'},{number: 'three', value: '3'},{number: 'divide', value: '/'}];



const button2 = [{number: 'four', value: '4'},{number: 'five', value: '5'},{number: 'six', value: '6'},{number: 'add', value: '+'}];



const button3 = [{number: 'seven', value: '7'},{number: 'eight', value: '8'},{number: 'nine', value: '9'},{number: 'subtract', value: '-'}];



const button4 = [{number: 'zero', value: '0'},{number: 'decimal', value: '.'},{number: 'equals', value: '='},{number: 'multiply', value: '*'}];





  class Calculator extends Component {

  constructor(props) {

    super(props);

    this.state = { value: "0"};

    this.handleClick = this.handleClick.bind(this);

  }





 handleClick(evt) {

    const id = evt.target.id;

    const result = evt.target.value;



switch(id) {

    case 'clear':

        this.setState({ value: "0"});

        break;

    case 'equals':

      this.setState(prevState => ({

        value: math.eval(this.state.value)

      }));

        break;



    default: this.setState(prevState => ({

        value: `${prevState.value}${result}`.replace(/([/+-/*=])([/+-*=])/g, "$2")

          .replace(/^0+(?=[1-9])/, "")

          .replace(/^0+(?=.)/, "0")

          .replace(/^0+B/, "")

          .replace(/.+/g,".")

      })); 

}





}















render() {

    return(

            <div id="container">

                <Display value={this.state.value} />

                <div>

  {button1.map((el, index) => <Button onClick={this.handleClick} key={el.index} id={el.number} value={el.value} />)}



                </div>

                <div>

 {button2.map((el, index)  => <Button onClick={this.handleClick} key={el.index} id={el.number} value={el.value} />)}

                </div>

                <div>

 {button3.map((el, index)  => <Button onClick={this.handleClick} key={el.index} id={el.number} value={el.value} />)}

                </div>

                <div>

{button4.map((el, index) => <Button onClick={this.handleClick} key={el.index} id={el.number} value={el.value} />)}

                </div>

                <div>

                <Button onClick={this.handleClick} id="clear" value={'clear'}  />

                </div>

            </div>

)



}



}

In Handle click, try replacing the default to below

  handleClick(evt) {

    const id = evt.target.id;

    let result = evt.target.value;



    switch (id) {

      case "clear":

        this.setState({ value: "0" });

        break;

      case "equals":

        this.setState(prevState => ({

          value: math.eval(this.state.value)

        }));

        break;



      default:

        this.setState(prevState => {

          const numbers = prevState.value.split(/[+-*=]/g);

          const lastNumber = numbers[numbers.length - 1];

          if (result === ".") {

            console.log((lastNumber.match(/./g) || ).length);

            if (lastNumber.length === 0) {

              result = ""; //Remove if first charracter is decimal

            }

            if ((lastNumber.match(/./g) || ).length > 0) {

              result = "";

            }

          }

          let value = `${prevState.value}${result}`

            .replace(/([+-*=])([+-*=])/g, "$2")

            .replace(/^0+(?=[1-9])/, "")

            .replace(/^0+(?=.)/, "0")

            .replace(/^0+B/, "");



          return {

            value

          };

        });

    }

  }

The method you're looking for is includes

EDIT per your additional information:

var positions = ;

for(i = 0; i < this.state.value.length; i++) {

    if(this.state.value.charAt(i) === result) {

        positions.push(i);

    }

}

You'll have to edit to fit your specific needs (I get the impression you're looking for something specific which you haven't overtly stated) but I imagine this gets you past your obstacle.