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Problem with updating object property in array of objects in React

I'm making an ecommrece project, in search bar I'm displaying checkboxes with categories from the API, all of those have value active == true by default. This is how I'm mapping them:

{categories.map((category) => {
       return (
              <>
             <input type="checkbox" onClick={() => handleCheckbox(category)} 
             defaultChecked={category.active} key={category.name} />
             <label style={{marginLeft:"5px"}} htmlFor={category.name}>{category.name}</label><br/>
             </> 
)
})}

Then I run this function to change category.active property from true to false, when the exact checkbox is clicked, then I want to update this object using useState

const handleCheckbox = (category) => {
    let tempCategory = category
    if (tempCategory.active == true) {
        tempCategory.active = false;
    } else {
        tempCategory.active = true;
    }
    setCategories({...categories, [tempCategory.id]: tempCategory})
    console.log(category.active)
}

Unfortunetly when I click on the checkbox I'm getting an error from React:

TypeError: categories.map is not a function

And it points to categories.map, I have no idea how to fix it. All I want is to update specific object in the categories array.

about 4 years ago · Juan Pablo Isaza
1 Respostas
Responde à pergunta

0

I believe your categories start life as an array of category objects, and you meant to setCategories to an array - but instead you're setting it to an object.

You also need to make sure you dont double up tempCategory. something like this:

setCategories([
 ...categories.filter(x => x.id != tempCategory.id), 
 tempCategory
]);

However, this will reorder your categories, putting tempCategory at the end, so another option is to slice the array correctly

const tmpIdx = categories.findIndex(x => x.id == tempCategory.id);
setCategories([
     ...categories.slice(0,tmpIdx), 
     tempCategory,
     ...categories.slice(tmpIdx+1), 
]);

Another option is make your categories an object and use Object.values(categories).map(...) but this makes ordering your categories harder, as there is no fixed ordering of object keys/values like there is with an array.

about 4 years ago · Juan Pablo Isaza Relatório
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