更新对象数组中的单个项目

Question

I have some data - I'd like to update a boolean in a single object.

The below works - It just seems like a really long way to do something so simple?

Also - If I were to change letter: "c" , it would be c at the front of the array, which would be incorrect. So is there a good way to maintain the order?

Thanks!!

// initial data
let data = [
  { letter: "a", number: 1, bool: true },
  { letter: "b", number: 2, bool: true },
  { letter: "c", number: 3, bool: true },
  { letter: "d", number: 4, bool: true },
  { letter: "e", number: 5, bool: true },
  { letter: "f", number: 6, bool: true },
  { letter: "g", number: 7, bool: true },
  { letter: "h", number: 8, bool: true },
  { letter: "i", number: 9, bool: true }
];

// get the row I need to change
const rowToChange = data.find(item => {
  return item.letter === "a";
});

// remove that row from data
data = data.filter(document => {
  return document !== rowToChange;
});

// updates the boolean value
rowToChange.bool = !rowToChange.bool;

// puts it back into the array
data = [rowToChange, ...data];

Answer 1

The method you're using is to (usually) ensure that you don't mutate the original data. If mutating the data is not an issue (and it doesn't look like it is) you can just drop some of the code. I've used findIndex here instead of find :

 let data = [ { letter: "a", number: 1, bool: true }, { letter: "b", number: 2, bool: true }, { letter: "c", number: 3, bool: true }, { letter: "d", number: 4, bool: true }, { letter: "e", number: 5, bool: true }, { letter: "f", number: 6, bool: true }, { letter: "g", number: 7, bool: true }, { letter: "h", number: 8, bool: true }, { letter: "i", number: 9, bool: true } ]; const rowToChange = data.findIndex(item => { return item.letter === "c"; }); data[rowToChange].bool =.data[rowToChange];bool. console;log(data);

Answer 2

you can do this, if you do not have some restrictions to the task

data.forEach(item => {
    if (item.letter == "a") {
       item.bool = !item.bool;
    }
});

Answer 3

With ES6, you can easily update a property of one object in your array using the map function:

let data = [
  { letter: "a", number: 1, bool: true },
  { letter: "b", number: 2, bool: true },
  { letter: "c", number: 3, bool: true },
  { letter: "d", number: 4, bool: true },
  { letter: "e", number: 5, bool: true },
  { letter: "f", number: 6, bool: true },
  { letter: "g", number: 7, bool: true },
  { letter: "h", number: 8, bool: true },
  { letter: "i", number: 9, bool: true }
];

console.log(data.map(d =>
  d.letter === 'c'
    ? { ...d, bool: false }
    : d
));

This will produce the following output:

[
  { letter: "a", number: 1, bool: true },
  { letter: "b", number: 2, bool: true },
  { letter: "c", number: 3, bool: false },
  { letter: "d", number: 4, bool: true },
  { letter: "e", number: 5, bool: true },
  { letter: "f", number: 6, bool: true },
  { letter: "g", number: 7, bool: true },
  { letter: "h", number: 8, bool: true },
  { letter: "i", number: 9, bool: true }
]