Adding clicked items to new array in React

Question

I am making API calls and rendering different components within an object. One of those is illustrated below:

class Bases extends Component {
    constructor() {
        super();

        this.state = {
            'basesObject': {}
        }
    }

    componentDidMount() {
        this.getBases();
    }

    getBases() {
        fetch('http://localhost:4000/cupcakes/bases')
        .then(results => results.json())
        .then(results => this.setState({'basesObject': results}))
    }

    render() {

        let {basesObject} = this.state;  
        let {bases} = basesObject; 

        console.log(bases); 
        //FALSY values: undefined, null, NaN, 0, false, ""

        return (

            <div>
                {bases && bases.map(item =>
                    <button key={item.key} className="boxes">
                        {/* <p>{item.key}</p> */}
                        <p>{item.name}</p>
                        <p>${item.price}.00</p>
                        {/* <p>{item.ingredients}</p> */}
                    </button>
            )}
           </div>
        )
    }
}

The above renders a set of buttons. All my components look basically the same.

I render my components here:

class App extends Component {
  state = {
    ordersArray: []
  }

  render() {
    return (
      <div>
        <h1>Bases</h1>
        <Bases />
        <h1>Frostings</h1>
        <Frostings />
        <h1>Toppings</h1>
        <Toppings />
      </div>
    );
  }
}

I need to figure out the simplest way to, when a button is clicked by the user, add the key of each clicked element to a new array and I am not sure where to start. The user must select one of each, but is allowed to select as many toppings as they want.

Oahehc · Accepted Answer · 2020-01-08 08:36:15Z

1

Try this

We can use the same component for all categories. All the data is handled by the parent (stateless component).

function Buttons({ list, handleClick }) {
  return (
    <div>
      {list.map(({ key, name, price, isSelected }) => (
        <button
          className={isSelected ? "active" : ""}
          key={key}
          onClick={() => handleClick(key)}
        >
          <span>{name}</span>
          <span>${price}</span>
        </button>
      ))}
    </div>
  );
}

Fetch data in App component, pass the data and handleClick method into Buttons.

class App extends Component {
  state = {
    basesArray: [],
    toppingsArray: []
  };

  componentDidMount() {
    // Get bases and toppings list, and add isSelected attribute with default value false
    this.setState({
      basesArray: [
        { key: "bases1", name: "bases1", price: 1, isSelected: false },
        { key: "bases2", name: "bases2", price: 2, isSelected: false },
        { key: "bases3", name: "bases3", price: 3, isSelected: false }
      ],
      toppingsArray: [
        { key: "topping1", name: "topping1", price: 1, isSelected: false },
        { key: "topping2", name: "topping2", price: 2, isSelected: false },
        { key: "topping3", name: "topping3", price: 3, isSelected: false }
      ]
    });
  }

  // for single selected category
  handleSingleSelected = type => key => {
    this.setState(state => ({
      [type]: state[type].map(item => ({
        ...item,
        isSelected: item.key === key
      }))
    }));
  };

  // for multiple selected category
  handleMultiSelected = type => key => {
    this.setState(state => ({
      [type]: state[type].map(item => {
        if (item.key === key) {
          return {
            ...item,
            isSelected: !item.isSelected
          };
        }
        return item;
      })
    }));
  };

  // get final selected item
  handleSubmit = () => {
    const { basesArray, toppingsArray } = this.state;
    const selectedBases = basesArray.filter(({ isSelected }) => isSelected);
    const selectedToppings = toppingsArray.filter(({ isSelected }) => isSelected);

    // submit the result here
  }

  render() {
    const { basesArray, toppingsArray } = this.state;

    return (
      <div>
        <h1>Bases</h1>
        <Buttons
          list={basesArray}
          handleClick={this.handleSingleSelected("basesArray")}
        />
        <h1>Toppings</h1>
        <Buttons
          list={toppingsArray}
          handleClick={this.handleMultiSelected("toppingsArray")}
        />
      </div>
    );
  }
}

export default App;

CSS

button {
  margin: 5px;
}
button.active {
  background: lightblue;
}

edited Jan 8, 2020 at 8:36

answered Jan 6, 2020 at 0:24

Oahehc

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6 Comments

Cory Allen Over a year ago

This almost works for me but I cant get the buttons to stay clicked like yours. To confirm, did you place the Buttons function at the top of the App.js file?

Cory Allen Over a year ago

Also this doesn't add the items into a new array. Im mostly confused on that part.

Oahehc Over a year ago

@CoryAllen did you place the Buttons function at the top of the App.js file -> Yes.

Oahehc Over a year ago

this doesn't add the items into a new array -> it will update the isSelected attribute at the original list, so just filter the list to get the selected items. I add this part into my answer for reference.

Cory Allen Over a year ago

can you post the css style you used too?

|

norbitrial · Accepted Answer · 2020-01-05 19:43:15Z

0

I think the following example would be a good start for your case.

Define a handleClick function where you can set state with setState as the following:

handleClick(item) {
  this.setState(prevState => {
    return {
       ...prevState,
       clickedItems: [...prevState.clickedItems, item.key]
    };
  });
}

Create an array called clickedItems in constructor for state and bind handleClick:

constructor() {
   super();
   this.state = {
      basesObject: {},
      clickedItems: [],
   }

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

You need to add a onClick={() => handleClick(item)} handler for onClick:

<button key={item.key} className="boxes" onClick={() => handleClick(item)}>
   {/* <p>{item.key}</p> */}
   <p>{item.name}</p>
   <p>${item.price}.00</p>
   {/* <p>{item.ingredients}</p> */}
</button>

I hope that helps!

edited Jan 5, 2020 at 19:43

answered Jan 5, 2020 at 19:37

norbitrial

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5 Comments

Cory Allen Over a year ago

This looks great, but what if I dont want to repeat myself? Is there any way I could do the handleClick function inside the App Component and call it on all my other components?

Wyck Over a year ago

You have a bug: If you write {...prevState, newClickedItems} it will rename clickedItems to newClickedItems Instead write: { ...prevState, clickedItems: [...prevState.clickedItems, item.key] }

norbitrial Over a year ago

@CoryAllen I guess then you need to create the state array in App level and pass down the click event through props to Bases component. So technically you are pushing from child component into parent component's array. I hope that clarifies.

Cory Allen Over a year ago

I'm not sure I understand what that would look like.

Cory Allen Over a year ago

It's not the bases I need added. I need 1 base, 1 frosting, and unlimited toppings. Those are the elements that need to go into the array.

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