Kevin Powell - Community•3y ago

Need help for local storage delete

I started learning about local storage recently and I'm wondering why is it when I delete some of the lists it doesn't delete from local storage. It's weird like when I have 5 list and delete them, some of them deleted fine, however some are gone form the html but not in the local storage. That is weird. Here is my code https://codepen.io/mingrkli/pen/RwyQwEe

Ming Li

CodePen

RwyQwEe

...

19 Replies

MarkBoots•3y ago

it is because you use the index of what is shown on the page. but when you remove something from local storage, the index there shifts, while the indexes on your button events still refer to the original index. what you can do is when you create a list, give it an unique id (new Date().getTime() for example) and let the delete button point to that id then you store the lists in an object with that id so your local storage would look something like this

const lists = {
  1664346995835: {
    text: "test",
    date: "Sep 28 2022"
  },
  1664347126037: {
    text: "test 2",
    date: "Sep 28 2022"
  },
}

const lists = {
  1664346995835: {
    text: "test",
    date: "Sep 28 2022"
  },
  1664347126037: {
    text: "test 2",
    date: "Sep 28 2022"
  },
}

that way when you click the delete button. you can delete it from localstorage by that id

kingtigerknight•3y ago

interesting. How would I target that ID to the local storage? I was thinking about creating an <p> that is hidden but I don't think that is great since if someone inspect the HTML if this was a different kind of project then they will see the ID.

MarkBoots•3y ago

just do the same. get it from local storage, and parse it. then you''ll have an object instead of an array. you can select the list by id lists[id_of_list]

kingtigerknight•3y ago

Oh... I just found a problem, how do I set the property by the parameter which is new Date().getTime() from your example?

MarkBoots•3y ago

you would append it to the existing lists

lists[getDateID] = {
  text: userText,
  ...
}

lists[getDateID] = {
  text: userText,
  ...
}

so listst is an object of objects

const lists = {
  "1664430910369" : {
    text: "bladiebla",
    name: "John Doe"
  },
  "1664431155891" : {
    text: "jodiejo",
    name: "Jane Doe" 
  }
}

const lists = {
  "1664430910369" : {
    text: "bladiebla",
    name: "John Doe"
  },
  "1664431155891" : {
    text: "jodiejo",
    name: "Jane Doe" 
  }
}

kingtigerknight•3y ago

Ah... so like this?

MarkBoots•3y ago

yea, and you dont have to push.

kingtigerknight•3y ago

oh ok, so it's like a 2 for 1. Thats cool

MarkBoots•3y ago

only the splice wont work now to delete from an object you do delete lists[datetimething]

kingtigerknight•3y ago

I'm guessing this would also need to be changed

kingtigerknight•3y ago

Ah ok, so for arrays we use forEach but for propertys we use for (list in lists). Ok i'm getting it now.

kingtigerknight•3y ago

oh... thats interesting.

kingtigerknight•3y ago

kingtigerknight•3y ago

I think I did something wrong XD

MarkBoots•3y ago

for in will give you the key

for(list in lists){
  console.log(lists[list]
}

for(list in lists){
  console.log(lists[list]
}

kingtigerknight•3y ago

Can you explain what lists[list] means for me to understand it? I know that for each list in the lists object, when I print the list it will show the list but I also thought it would show what is in thoses list as well. However to do that you need to print lists[list] instead. What dose lists[list] mean in this context?

MarkBoots•3y ago

as you have seen, list will give you only the datetime (that is the key of the object entry) to access the values of a specific object entry you do objectname[objectkey] in your case the object name is lists and the object key is the datetime

kingtigerknight•3y ago

Ah ok, thankyou for all the information 🙂

MarkBoots•3y ago

no problem, good luck

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Need help for local storage delete