How to replace a value in localstorage using javascript?-CodePudding

If the value is exist in localstorage I want to replace it. When I try to do that existing value is still inserting.

  addEntry = (e,id) => {
  
  e.preventDefault()

  let product_list = []
  let productCost = document.getElementById('projectcost').value;
  let productQty = document.getElementById('productQty' id).value;
  let productId = id;

  if(localStorage.getItem('myItems')){
  
    product_list = JSON.parse(localStorage.getItem('myItems'))
    product_list.push({productId,productCost,productQty})
    localStorage.setItem('myItems',JSON.stringify(product_list))

   }else{
   
    product_list.push({productId,productCost,productQty})
    localStorage.setItem('myItems',JSON.stringify([{productId,productCost,productQty}]))
   }
}

Output

[{"productId":43,"productCost":"320","productQty":"2"},{"productId":43,"productCost":"480","productQty":"3"},{"productId":44,"productCost":"420","productQty":"3"}]

When I want to insert same value I want the output to be

[{"productId":43,"productCost":"480","productQty":"3"},{"productId":44,"productCost":"420","productQty":"3"}]

CodePudding user response：

To avoid that you push the same product a second time, first filter out the object that might concern the same product:

let productCost =  document.getElementById('projectcost').value;
let productQty =  document.getElementById('productQty' id).value;
let product_list = JSON.parse(localStorage.getItem('myItems') ?? "[]");
                       .filter(({productId}) => productId != id)
                       .concat({productId: id, productCost, productQty});
localStorage.setItem('myItems', JSON.stringify(product_list));