React - How To Compare Props Between Separate Components












1















How can I compare if the props between two separate components have the same value?



1- Is what I'm seeking doable?



2- If not, how else could I accomplish the ask below:



The story:




  • I have an array of car objects.
    Each car's name is displayed as <li /> on a <CarList /> component.
    Upon click on each <li/> the car's color is revealed


  • I have a <Question /> component that renders: "What car is (random color here)"?



UI change:
How could I write a method that:




  • Checks if the props.color of <CarList /> === the props.color of <Question />

  • Then it fires a UI change such as:


  • onClick: If the car's color matches the question's color: change the <li /> to green (ie: background-color), else change it to red.


I'm struggling (wondering if it's possible) to compare props from different components + writing a method that checks and executes the UI change above.



This is the code reflecting the explanation above: Also here's the sandbox



// Garage
export default class Garage extends Component {
state = {
cars: [
{ name: "Ferrari", color: "red", id: 1 },
{ name: "Porsche", color: "black", id: 2 },
{ name: "lamborghini", color: "green", id: 3 },
{ name: "McLaren", color: "silver", id: 4 },
{ name: "Tesla", color: "yellow", id: 5 }
]
};

handleShuffle = () => {
this.setState({
cars: [...this.state.cars.sort(() => Math.random() - 0.5)]
});
};

render() {
const { cars } = this.state;
const car = cars.map(car => (
<CarList key={car.id} make={car.name} color={car.color} />
));

const guess = cars
.slice(2, 3)
.map(car => <Question key={car.id} color={car.color} />);
return (
<>
<div>{guess}</div>
<button onClick={this.handleShuffle}>load color</button>
<ul>{car}</ul>
</>
);
}
}

// CarList
class CarList extends Component {
state = {
show: false
};

handleShow = () => {
this.setState({ show: true });
console.log(this.props);
// check for props equality here

//desired result for <li /> would be
// className={ correctColor ? 'green' : 'red'}
};

render() {
console.log("car color props:", this.props.color);
const { make, color } = this.props;
const { show } = this.state;
return (
<li onClick={this.handleShow}>
{make}
<span className={show ? "show" : "hide"}>{color}</span>
</li>
);
}
}

// Question
const Question = ({ color }) =>
console.log("question color prop:", color) || <h1>What car is {color}</h1>;









share|improve this question





























    1















    How can I compare if the props between two separate components have the same value?



    1- Is what I'm seeking doable?



    2- If not, how else could I accomplish the ask below:



    The story:




    • I have an array of car objects.
      Each car's name is displayed as <li /> on a <CarList /> component.
      Upon click on each <li/> the car's color is revealed


    • I have a <Question /> component that renders: "What car is (random color here)"?



    UI change:
    How could I write a method that:




    • Checks if the props.color of <CarList /> === the props.color of <Question />

    • Then it fires a UI change such as:


    • onClick: If the car's color matches the question's color: change the <li /> to green (ie: background-color), else change it to red.


    I'm struggling (wondering if it's possible) to compare props from different components + writing a method that checks and executes the UI change above.



    This is the code reflecting the explanation above: Also here's the sandbox



    // Garage
    export default class Garage extends Component {
    state = {
    cars: [
    { name: "Ferrari", color: "red", id: 1 },
    { name: "Porsche", color: "black", id: 2 },
    { name: "lamborghini", color: "green", id: 3 },
    { name: "McLaren", color: "silver", id: 4 },
    { name: "Tesla", color: "yellow", id: 5 }
    ]
    };

    handleShuffle = () => {
    this.setState({
    cars: [...this.state.cars.sort(() => Math.random() - 0.5)]
    });
    };

    render() {
    const { cars } = this.state;
    const car = cars.map(car => (
    <CarList key={car.id} make={car.name} color={car.color} />
    ));

    const guess = cars
    .slice(2, 3)
    .map(car => <Question key={car.id} color={car.color} />);
    return (
    <>
    <div>{guess}</div>
    <button onClick={this.handleShuffle}>load color</button>
    <ul>{car}</ul>
    </>
    );
    }
    }

    // CarList
    class CarList extends Component {
    state = {
    show: false
    };

    handleShow = () => {
    this.setState({ show: true });
    console.log(this.props);
    // check for props equality here

    //desired result for <li /> would be
    // className={ correctColor ? 'green' : 'red'}
    };

    render() {
    console.log("car color props:", this.props.color);
    const { make, color } = this.props;
    const { show } = this.state;
    return (
    <li onClick={this.handleShow}>
    {make}
    <span className={show ? "show" : "hide"}>{color}</span>
    </li>
    );
    }
    }

    // Question
    const Question = ({ color }) =>
    console.log("question color prop:", color) || <h1>What car is {color}</h1>;









    share|improve this question



























      1












      1








      1


      1






      How can I compare if the props between two separate components have the same value?



      1- Is what I'm seeking doable?



      2- If not, how else could I accomplish the ask below:



      The story:




      • I have an array of car objects.
        Each car's name is displayed as <li /> on a <CarList /> component.
        Upon click on each <li/> the car's color is revealed


      • I have a <Question /> component that renders: "What car is (random color here)"?



      UI change:
      How could I write a method that:




      • Checks if the props.color of <CarList /> === the props.color of <Question />

      • Then it fires a UI change such as:


      • onClick: If the car's color matches the question's color: change the <li /> to green (ie: background-color), else change it to red.


      I'm struggling (wondering if it's possible) to compare props from different components + writing a method that checks and executes the UI change above.



      This is the code reflecting the explanation above: Also here's the sandbox



      // Garage
      export default class Garage extends Component {
      state = {
      cars: [
      { name: "Ferrari", color: "red", id: 1 },
      { name: "Porsche", color: "black", id: 2 },
      { name: "lamborghini", color: "green", id: 3 },
      { name: "McLaren", color: "silver", id: 4 },
      { name: "Tesla", color: "yellow", id: 5 }
      ]
      };

      handleShuffle = () => {
      this.setState({
      cars: [...this.state.cars.sort(() => Math.random() - 0.5)]
      });
      };

      render() {
      const { cars } = this.state;
      const car = cars.map(car => (
      <CarList key={car.id} make={car.name} color={car.color} />
      ));

      const guess = cars
      .slice(2, 3)
      .map(car => <Question key={car.id} color={car.color} />);
      return (
      <>
      <div>{guess}</div>
      <button onClick={this.handleShuffle}>load color</button>
      <ul>{car}</ul>
      </>
      );
      }
      }

      // CarList
      class CarList extends Component {
      state = {
      show: false
      };

      handleShow = () => {
      this.setState({ show: true });
      console.log(this.props);
      // check for props equality here

      //desired result for <li /> would be
      // className={ correctColor ? 'green' : 'red'}
      };

      render() {
      console.log("car color props:", this.props.color);
      const { make, color } = this.props;
      const { show } = this.state;
      return (
      <li onClick={this.handleShow}>
      {make}
      <span className={show ? "show" : "hide"}>{color}</span>
      </li>
      );
      }
      }

      // Question
      const Question = ({ color }) =>
      console.log("question color prop:", color) || <h1>What car is {color}</h1>;









      share|improve this question
















      How can I compare if the props between two separate components have the same value?



      1- Is what I'm seeking doable?



      2- If not, how else could I accomplish the ask below:



      The story:




      • I have an array of car objects.
        Each car's name is displayed as <li /> on a <CarList /> component.
        Upon click on each <li/> the car's color is revealed


      • I have a <Question /> component that renders: "What car is (random color here)"?



      UI change:
      How could I write a method that:




      • Checks if the props.color of <CarList /> === the props.color of <Question />

      • Then it fires a UI change such as:


      • onClick: If the car's color matches the question's color: change the <li /> to green (ie: background-color), else change it to red.


      I'm struggling (wondering if it's possible) to compare props from different components + writing a method that checks and executes the UI change above.



      This is the code reflecting the explanation above: Also here's the sandbox



      // Garage
      export default class Garage extends Component {
      state = {
      cars: [
      { name: "Ferrari", color: "red", id: 1 },
      { name: "Porsche", color: "black", id: 2 },
      { name: "lamborghini", color: "green", id: 3 },
      { name: "McLaren", color: "silver", id: 4 },
      { name: "Tesla", color: "yellow", id: 5 }
      ]
      };

      handleShuffle = () => {
      this.setState({
      cars: [...this.state.cars.sort(() => Math.random() - 0.5)]
      });
      };

      render() {
      const { cars } = this.state;
      const car = cars.map(car => (
      <CarList key={car.id} make={car.name} color={car.color} />
      ));

      const guess = cars
      .slice(2, 3)
      .map(car => <Question key={car.id} color={car.color} />);
      return (
      <>
      <div>{guess}</div>
      <button onClick={this.handleShuffle}>load color</button>
      <ul>{car}</ul>
      </>
      );
      }
      }

      // CarList
      class CarList extends Component {
      state = {
      show: false
      };

      handleShow = () => {
      this.setState({ show: true });
      console.log(this.props);
      // check for props equality here

      //desired result for <li /> would be
      // className={ correctColor ? 'green' : 'red'}
      };

      render() {
      console.log("car color props:", this.props.color);
      const { make, color } = this.props;
      const { show } = this.state;
      return (
      <li onClick={this.handleShow}>
      {make}
      <span className={show ? "show" : "hide"}>{color}</span>
      </li>
      );
      }
      }

      // Question
      const Question = ({ color }) =>
      console.log("question color prop:", color) || <h1>What car is {color}</h1>;






      javascript reactjs ecmascript-6 react-props






      share|improve this question















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      share|improve this question




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      edited Nov 20 '18 at 22:23







      Jonca33

















      asked Nov 20 '18 at 22:08









      Jonca33Jonca33

      1,1421020




      1,1421020
























          2 Answers
          2






          active

          oldest

          votes


















          2














          Yes, you can pass the correct color to the CarList component or the flag whether the CarList is a correct one. Check my sandbox.



          https://codesandbox.io/s/92xnwpyq6p



          Basically we can add isCorrect prop to CarList which has value of correctCar.color === car.color and we use it to determine whether we should render it green or red.






          share|improve this answer
























          • Thank you so much for the explanation and code example. Ideally red or green only triggers upon clicking. Prior to it, it should stay in black. Would/Should I massage this logic on className={.....}?

            – Jonca33
            Nov 20 '18 at 22:48













          • you can use empty string in that case. I think I also use it in my sandbox. Check it out

            – jamesjaya
            Nov 20 '18 at 22:54






          • 1





            check my getColor() function

            – jamesjaya
            Nov 20 '18 at 23:04






          • 1





            Garage.js line 62 correctIndex: Math.random() returns a random number between 0 and 1. I multiply it by the length of cars minus 1, means if the length is 5, the random number would be a random number between 0 and 4. Since I want an integer, I call Math.floor.

            – jamesjaya
            Nov 20 '18 at 23:17






          • 1





            oh I forgot to hit save, you should be able to see it now

            – jamesjaya
            Nov 20 '18 at 23:32



















          2














          Theres many ways to do this but the simplest is to send the color in the question down to the car component.



          https://codesandbox.io/s/my4wmn427x






          share|improve this answer
























          • Thank you! So with this approach where/how <Question/> becomes aware of the questionColor sent down to <CarList />?

            – Jonca33
            Nov 20 '18 at 23:45






          • 1





            <Question> is not aware it's color is being sent to <CarList>. In this approach the garage is aware of both colors and chooses to additionally send down the question color to <CarList> so that each car can do a comparison against its own car color :)

            – Shawn Andrews
            Nov 21 '18 at 5:25











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          2 Answers
          2






          active

          oldest

          votes








          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          2














          Yes, you can pass the correct color to the CarList component or the flag whether the CarList is a correct one. Check my sandbox.



          https://codesandbox.io/s/92xnwpyq6p



          Basically we can add isCorrect prop to CarList which has value of correctCar.color === car.color and we use it to determine whether we should render it green or red.






          share|improve this answer
























          • Thank you so much for the explanation and code example. Ideally red or green only triggers upon clicking. Prior to it, it should stay in black. Would/Should I massage this logic on className={.....}?

            – Jonca33
            Nov 20 '18 at 22:48













          • you can use empty string in that case. I think I also use it in my sandbox. Check it out

            – jamesjaya
            Nov 20 '18 at 22:54






          • 1





            check my getColor() function

            – jamesjaya
            Nov 20 '18 at 23:04






          • 1





            Garage.js line 62 correctIndex: Math.random() returns a random number between 0 and 1. I multiply it by the length of cars minus 1, means if the length is 5, the random number would be a random number between 0 and 4. Since I want an integer, I call Math.floor.

            – jamesjaya
            Nov 20 '18 at 23:17






          • 1





            oh I forgot to hit save, you should be able to see it now

            – jamesjaya
            Nov 20 '18 at 23:32
















          2














          Yes, you can pass the correct color to the CarList component or the flag whether the CarList is a correct one. Check my sandbox.



          https://codesandbox.io/s/92xnwpyq6p



          Basically we can add isCorrect prop to CarList which has value of correctCar.color === car.color and we use it to determine whether we should render it green or red.






          share|improve this answer
























          • Thank you so much for the explanation and code example. Ideally red or green only triggers upon clicking. Prior to it, it should stay in black. Would/Should I massage this logic on className={.....}?

            – Jonca33
            Nov 20 '18 at 22:48













          • you can use empty string in that case. I think I also use it in my sandbox. Check it out

            – jamesjaya
            Nov 20 '18 at 22:54






          • 1





            check my getColor() function

            – jamesjaya
            Nov 20 '18 at 23:04






          • 1





            Garage.js line 62 correctIndex: Math.random() returns a random number between 0 and 1. I multiply it by the length of cars minus 1, means if the length is 5, the random number would be a random number between 0 and 4. Since I want an integer, I call Math.floor.

            – jamesjaya
            Nov 20 '18 at 23:17






          • 1





            oh I forgot to hit save, you should be able to see it now

            – jamesjaya
            Nov 20 '18 at 23:32














          2












          2








          2







          Yes, you can pass the correct color to the CarList component or the flag whether the CarList is a correct one. Check my sandbox.



          https://codesandbox.io/s/92xnwpyq6p



          Basically we can add isCorrect prop to CarList which has value of correctCar.color === car.color and we use it to determine whether we should render it green or red.






          share|improve this answer













          Yes, you can pass the correct color to the CarList component or the flag whether the CarList is a correct one. Check my sandbox.



          https://codesandbox.io/s/92xnwpyq6p



          Basically we can add isCorrect prop to CarList which has value of correctCar.color === car.color and we use it to determine whether we should render it green or red.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 20 '18 at 22:38









          jamesjayajamesjaya

          657412




          657412













          • Thank you so much for the explanation and code example. Ideally red or green only triggers upon clicking. Prior to it, it should stay in black. Would/Should I massage this logic on className={.....}?

            – Jonca33
            Nov 20 '18 at 22:48













          • you can use empty string in that case. I think I also use it in my sandbox. Check it out

            – jamesjaya
            Nov 20 '18 at 22:54






          • 1





            check my getColor() function

            – jamesjaya
            Nov 20 '18 at 23:04






          • 1





            Garage.js line 62 correctIndex: Math.random() returns a random number between 0 and 1. I multiply it by the length of cars minus 1, means if the length is 5, the random number would be a random number between 0 and 4. Since I want an integer, I call Math.floor.

            – jamesjaya
            Nov 20 '18 at 23:17






          • 1





            oh I forgot to hit save, you should be able to see it now

            – jamesjaya
            Nov 20 '18 at 23:32



















          • Thank you so much for the explanation and code example. Ideally red or green only triggers upon clicking. Prior to it, it should stay in black. Would/Should I massage this logic on className={.....}?

            – Jonca33
            Nov 20 '18 at 22:48













          • you can use empty string in that case. I think I also use it in my sandbox. Check it out

            – jamesjaya
            Nov 20 '18 at 22:54






          • 1





            check my getColor() function

            – jamesjaya
            Nov 20 '18 at 23:04






          • 1





            Garage.js line 62 correctIndex: Math.random() returns a random number between 0 and 1. I multiply it by the length of cars minus 1, means if the length is 5, the random number would be a random number between 0 and 4. Since I want an integer, I call Math.floor.

            – jamesjaya
            Nov 20 '18 at 23:17






          • 1





            oh I forgot to hit save, you should be able to see it now

            – jamesjaya
            Nov 20 '18 at 23:32

















          Thank you so much for the explanation and code example. Ideally red or green only triggers upon clicking. Prior to it, it should stay in black. Would/Should I massage this logic on className={.....}?

          – Jonca33
          Nov 20 '18 at 22:48







          Thank you so much for the explanation and code example. Ideally red or green only triggers upon clicking. Prior to it, it should stay in black. Would/Should I massage this logic on className={.....}?

          – Jonca33
          Nov 20 '18 at 22:48















          you can use empty string in that case. I think I also use it in my sandbox. Check it out

          – jamesjaya
          Nov 20 '18 at 22:54





          you can use empty string in that case. I think I also use it in my sandbox. Check it out

          – jamesjaya
          Nov 20 '18 at 22:54




          1




          1





          check my getColor() function

          – jamesjaya
          Nov 20 '18 at 23:04





          check my getColor() function

          – jamesjaya
          Nov 20 '18 at 23:04




          1




          1





          Garage.js line 62 correctIndex: Math.random() returns a random number between 0 and 1. I multiply it by the length of cars minus 1, means if the length is 5, the random number would be a random number between 0 and 4. Since I want an integer, I call Math.floor.

          – jamesjaya
          Nov 20 '18 at 23:17





          Garage.js line 62 correctIndex: Math.random() returns a random number between 0 and 1. I multiply it by the length of cars minus 1, means if the length is 5, the random number would be a random number between 0 and 4. Since I want an integer, I call Math.floor.

          – jamesjaya
          Nov 20 '18 at 23:17




          1




          1





          oh I forgot to hit save, you should be able to see it now

          – jamesjaya
          Nov 20 '18 at 23:32





          oh I forgot to hit save, you should be able to see it now

          – jamesjaya
          Nov 20 '18 at 23:32













          2














          Theres many ways to do this but the simplest is to send the color in the question down to the car component.



          https://codesandbox.io/s/my4wmn427x






          share|improve this answer
























          • Thank you! So with this approach where/how <Question/> becomes aware of the questionColor sent down to <CarList />?

            – Jonca33
            Nov 20 '18 at 23:45






          • 1





            <Question> is not aware it's color is being sent to <CarList>. In this approach the garage is aware of both colors and chooses to additionally send down the question color to <CarList> so that each car can do a comparison against its own car color :)

            – Shawn Andrews
            Nov 21 '18 at 5:25
















          2














          Theres many ways to do this but the simplest is to send the color in the question down to the car component.



          https://codesandbox.io/s/my4wmn427x






          share|improve this answer
























          • Thank you! So with this approach where/how <Question/> becomes aware of the questionColor sent down to <CarList />?

            – Jonca33
            Nov 20 '18 at 23:45






          • 1





            <Question> is not aware it's color is being sent to <CarList>. In this approach the garage is aware of both colors and chooses to additionally send down the question color to <CarList> so that each car can do a comparison against its own car color :)

            – Shawn Andrews
            Nov 21 '18 at 5:25














          2












          2








          2







          Theres many ways to do this but the simplest is to send the color in the question down to the car component.



          https://codesandbox.io/s/my4wmn427x






          share|improve this answer













          Theres many ways to do this but the simplest is to send the color in the question down to the car component.



          https://codesandbox.io/s/my4wmn427x







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 20 '18 at 22:42









          Shawn AndrewsShawn Andrews

          975617




          975617













          • Thank you! So with this approach where/how <Question/> becomes aware of the questionColor sent down to <CarList />?

            – Jonca33
            Nov 20 '18 at 23:45






          • 1





            <Question> is not aware it's color is being sent to <CarList>. In this approach the garage is aware of both colors and chooses to additionally send down the question color to <CarList> so that each car can do a comparison against its own car color :)

            – Shawn Andrews
            Nov 21 '18 at 5:25



















          • Thank you! So with this approach where/how <Question/> becomes aware of the questionColor sent down to <CarList />?

            – Jonca33
            Nov 20 '18 at 23:45






          • 1





            <Question> is not aware it's color is being sent to <CarList>. In this approach the garage is aware of both colors and chooses to additionally send down the question color to <CarList> so that each car can do a comparison against its own car color :)

            – Shawn Andrews
            Nov 21 '18 at 5:25

















          Thank you! So with this approach where/how <Question/> becomes aware of the questionColor sent down to <CarList />?

          – Jonca33
          Nov 20 '18 at 23:45





          Thank you! So with this approach where/how <Question/> becomes aware of the questionColor sent down to <CarList />?

          – Jonca33
          Nov 20 '18 at 23:45




          1




          1





          <Question> is not aware it's color is being sent to <CarList>. In this approach the garage is aware of both colors and chooses to additionally send down the question color to <CarList> so that each car can do a comparison against its own car color :)

          – Shawn Andrews
          Nov 21 '18 at 5:25





          <Question> is not aware it's color is being sent to <CarList>. In this approach the garage is aware of both colors and chooses to additionally send down the question color to <CarList> so that each car can do a comparison against its own car color :)

          – Shawn Andrews
          Nov 21 '18 at 5:25


















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