How to update Nested object in react state?

Question

This is the current state

state={
    product:[
        {id:1, title: 'demo product 1 ', price: 10, incart: 2},
        {id:2, title: 'demo product 2', price: 11, incart: 3},
    
    
    ],
}

I have a +1 button that increase the total number of product in incart.

// the onClick handler 
// prod arguments return a product object like this {id:1, title: 'demo product 1 ', price: 10, incart: 2}

handelIncrement= (prod) => {
    
    const newState = {...this.state.product, prod}  
    this.setState({ product: newState })  // giving an error
    
  }

I appreciate your help 🙏

Meet Majevadiya · Accepted Answer · 2022-07-11 05:41:24Z

2

what you are doing is you pass an object to a product state and a product state is an array.

handelIncrement= (prod) => {
    
    const newState = [...this.state.product, prod]  
    this.setState({ product: newState })  // giving an error
    
  }

answered Jul 11, 2022 at 5:41

Meet Majevadiya

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4 Comments

Abu Hayat Over a year ago

I see, how can I overwrite the child object of the array? my approach [...this.state.product, prod] adding a new object into the array. but I want to overwrite the previous object that has the same id as prod.id

Meet Majevadiya Over a year ago

Then the best approach is using then index to update the data

Abu Hayat Over a year ago

Would you please show me the code? I am not an expert.

Meet Majevadiya Over a year ago

Sure I will upload the code and you need to pass the current object index to the method.

Hitesh Navapariya · Accepted Answer · 2022-07-11 06:35:37Z

0

handleIncrement= (prod) => {
    
    this.setState({
      data: this.state.product.map(el => (el.id === id ? {...el, text} : el))
    });
    
  }

answered Jul 11, 2022 at 6:35

Hitesh Navapariya

1

Comments

Meet Majevadiya · Accepted Answer · 2022-07-11 08:21:07Z

0

To handleincrement() method you need to pass index to method to that.

handelIncrement= (index,prod) => {
    //first copy data
    const copyProducts = [...product];
    //copy current object data
    const singleObjectData = { ...copyProducts[index] };
    //change object data
    singleObjectData = {//your new current prod};
    //put back to the same index
    copyProducts[index] = singleObjectData;
    //and update set
     this.setState({ product: copyProducts })
  }

answered Jul 11, 2022 at 8:21

Meet Majevadiya

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