Dynamically change data in array

Question

I have an array

Array [
  "2022-03-25",
  "2022-03-10",
  "2022-03-24",
  "2022-03-31",
  "2022-03-12",
  "2022-03-23",
  "2022-03-22",
  "2022-03-16",
  "2022-03-11",
  "2022-03-26",
]

And I have the data of objects:

 Object {
  "2022-03-10": Object {
    "marked": true,
  },
  "2022-03-11": Object {
    "marked": true,
  },
  "2022-03-12": Object {
    "marked": true,
  },
  "2022-03-16": Object {
    "marked": true,
  },
  "2022-03-18": Object {
    "marked": true,
  },
  "2022-03-22": Object {
    "marked": true,
  },
  "2022-03-23": Object {
    "marked": true,
  },
  "2022-03-24": Object {
    "marked": true,
  },
  "2022-03-25": Object {
    "marked": true,
  },
  "2022-03-26": Object {
    "marked": true,
  },
  "2022-03-27": Object {
    "marked": true,
  },
  "2022-03-31": Object {
    "marked": true,
  },
}

In the objects, theres is a date "2022-03-27", however, it is not in the array. What I would like to do is, if the date is not in the ARRAY, I would like to remove it from the object, or mark it as false.

pilchard · Accepted Answer · 2022-03-29 22:45:55Z

To avoid mutating the original object you can use Object.fromEntries passing the filtered Object.entries of the original. Here simply using filter() and testing using includes().

const array = ["2022-03-25", "2022-03-10", "2022-03-24", "2022-03-31", "2022-03-12", "2022-03-23", "2022-03-22", "2022-03-16", "2022-03-11", "2022-03-26",];
const object = { "2022-03-10": { "marked": true, }, "2022-03-11": { "marked": true, }, "2022-03-12": { "marked": true, }, "2022-03-16": { "marked": true, }, "2022-03-18": { "marked": true, }, "2022-03-22": { "marked": true, }, "2022-03-23": { "marked": true, }, "2022-03-24": { "marked": true, }, "2022-03-25": { "marked": true, }, "2022-03-26": { "marked": true, }, "2022-03-27": { "marked": true, }, "2022-03-31": { "marked": true, }, };

const filteredObject = Object.fromEntries(
  Object.entries(object)
    .filter(([key]) => array.includes(key))
);

console.log(filteredObject);

To instead toggle the marked properties of each nested object you can use a similar method, but instead of filter() you can map() the original Object.entries here using spread syntax to clone each nested object and overwrite the marked property with the result of the same includes() call as the previous example.

const array = ["2022-03-25", "2022-03-10", "2022-03-24", "2022-03-31", "2022-03-12", "2022-03-23", "2022-03-22", "2022-03-16", "2022-03-11", "2022-03-26",];
const object = { "2022-03-10": { "marked": true, }, "2022-03-11": { "marked": true, }, "2022-03-12": { "marked": true, }, "2022-03-16": { "marked": true, }, "2022-03-18": { "marked": true, }, "2022-03-22": { "marked": true, }, "2022-03-23": { "marked": true, }, "2022-03-24": { "marked": true, }, "2022-03-25": { "marked": true, }, "2022-03-26": { "marked": true, }, "2022-03-27": { "marked": true, }, "2022-03-31": { "marked": true, }, };

const markedObject = Object.fromEntries(
  Object.entries(object)
    .map(([key, value]) => [key, { ...value, marked: array.includes(key) }])
);

console.log(markedObject);

Tibrogargan · Accepted Answer · 2022-03-29 23:05:24Z

1

I'm taking all the keys of your object, then iterating over the collection and updating the marked property according to whether the date is included in the Array.
Assumption: The objects Object is being used to track state and so is intended to be mutable.

let dates = [ "2022-03-25", "2022-03-10", "2022-03-24", "2022-03-31", "2022-03-12",
              "2022-03-23", "2022-03-22", "2022-03-16", "2022-03-11", "2022-03-26" ]
let objects = { "2022-03-10": { marked: true }, "2022-03-11": { marked: true },
                "2022-03-12": { marked: true }, "2022-03-16": { marked: true },
                "2022-03-18": { marked: true }, "2022-03-22": { marked: true },
                "2022-03-23": { marked: true }, "2022-03-24": { marked: true },
                "2022-03-25": { marked: true }, "2022-03-26": { marked: true },
                "2022-03-27": { marked: true }, "2022-03-31": { marked: true }
}
keySet = Object.keys(objects)
keySet.forEach( key => objects[ key ].marked = dates.includes(key) )
console.log(objects)

In order to avoid updating objects that have no meaningful change, you could do this instead:

Object.keys(objects).filter(date => !dates.includes(date)).map( date =>  objects[ date ].marked = false )
console.log(objects)

edited Mar 29, 2022 at 23:05

answered Mar 29, 2022 at 22:54

Tibrogargan

4,6323 gold badges21 silver badges41 bronze badges

2 Comments

Carlos Craig Over a year ago

This was simple and perfect, thank you very much

Tibrogargan Over a year ago

Thanks. Probably better to use forEach rather than map in the 2nd version. Misuse of map.

Salman Arshad · Accepted Answer · 2022-03-29 22:45:24Z

1

Iterate over object keys, find if the key exists in the array, delete it from the object if not found:

Object.keys(obj).forEach(function(key) {
    if (arr.includes(key) === false) {
        delete obj[key];
    }
});

edited Mar 29, 2022 at 22:45

answered Mar 29, 2022 at 22:28

Salman Arshad

274k85 gold badges450 silver badges540 bronze badges

1 Comment

Salman Arshad Over a year ago

Note to the editor: Array.map is supposed to transform the array into another array and you're interested in return value. It is a bad choice in this case.

TMG · Accepted Answer · 2022-03-29 22:25:41Z

0

You could use the Array.prototype.includes() method. Just extract the value from your object and use a conditional statement.

if array.includes(yourObjectDate) {
return true
} else {
return false
}

answered Mar 29, 2022 at 22:25

TMG

212 bronze badges

Comments

Gotzi · Accepted Answer · 2022-03-29 23:39:59Z

0

for (const property in object) {
  array.find(date => object[property].marked = date === property);
}

edited Mar 29, 2022 at 23:39

answered Mar 29, 2022 at 22:42

Gotzi

494 bronze badges

2 Comments

Gotzi Over a year ago

Actually that isn't true. I was marking true instead of false jsfiddle.net/9fbrvj5a . updated response above.

Tibrogargan Over a year ago

You probably want to avoid patterns like this. You're modifying every element of object once for every element of array. This is O(n^2) instead of O(n), and write operations tend to be significantly more expensive than read operations.

PeterKA · Accepted Answer · 2022-03-30 00:07:25Z

Here's how to remove the object whose date is not in dates:

let dates = [ "2022-03-25", "2022-03-10", "2022-03-24", "2022-03-31", "2022-03-12", "2022-03-23", "2022-03-22", "2022-03-16", "2022-03-11", "2022-03-26" ];
let objects = { "2022-03-10": { marked: true }, "2022-03-11": { marked: true }, "2022-03-12": { marked: true }, "2022-03-16": { marked: true }, "2022-03-18": { marked: true }, "2022-03-22": { marked: true }, "2022-03-23": { marked: true }, "2022-03-24": { marked: true }, "2022-03-25": { marked: true }, "2022-03-26": { marked: true }, "2022-03-27": { marked: true }, "2022-03-31": { marked: true } };

Object.keys(objects).forEach(
    key => dates.includes(key) || delete objects[key]
); 

console.log(objects)

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