The first one is an array of objects:

let objectArray = [{
    FullName: "Person1",
    PersonId: "id1"
  },
  {
    FullName: "Person2",
    PersonId: "id2"
  },
  {
    FullName: "Person3",
    PersonId: "id3"
  },
  {
    FullName: "Person4",
    PersonId: "id4"
  }
];

The second one is an array of strings containing some ids.

let idsArray= ["id1", "id2", "id3"];

I need to delete the objects of the first array whose id are contained in the second array.

Expected result:

firstArray = [{
  FullName: "Person4",
  PersonId: "id4"
}];

Exploring Linqjs documentation I discovered that the Except() method allows me to remove elements from the first array using the second one as the "filter".

In order to use this method, I need to create a new array from objectArray that contains only the elements whose ids are contained on idsArray to use it as a parameter.

Example:

let filteredArray = Enumerable.From(objectArray).Except(theNewArray).ToArray();

To create this new array I can use the method Where() from Linqjs.

My problem starts here because I don't know how to create this new array considering that I have an array of ids to filter.

The first one is an array of objects:

let objectArray = [{
    FullName: "Person1",
    PersonId: "id1"
  },
  {
    FullName: "Person2",
    PersonId: "id2"
  },
  {
    FullName: "Person3",
    PersonId: "id3"
  },
  {
    FullName: "Person4",
    PersonId: "id4"
  }
];

The second one is an array of strings containing some ids.

let idsArray= ["id1", "id2", "id3"];

I need to delete the objects of the first array whose id are contained in the second array.

Expected result:

firstArray = [{
  FullName: "Person4",
  PersonId: "id4"
}];

Exploring Linqjs documentation I discovered that the Except() method allows me to remove elements from the first array using the second one as the "filter".

In order to use this method, I need to create a new array from objectArray that contains only the elements whose ids are contained on idsArray to use it as a parameter.

Example:

let filteredArray = Enumerable.From(objectArray).Except(theNewArray).ToArray();

To create this new array I can use the method Where() from Linqjs.

My problem starts here because I don't know how to create this new array considering that I have an array of ids to filter.

• javascript
• arrays
• linq.js

4 Answers 4

You can use Vanilla JavaScript's array.filter and array.includes like this:

let objectArray = [
  {FullName: "Person1", PersonId: "id1"},
  {FullName: "Person2", PersonId: "id2"},
  {FullName: "Person3", PersonId: "id3"},
  {FullName: "Person4", PersonId: "id4"}
];
    
  let excludeIdsArray= ["id1", "id2", "id3"];
  
  let newObj = objectArray.filter(obj => !excludeIdsArray.includes(obj.PersonId))
  
  console.log(newObj)

Or, you can use array.reduce and array.includes like this:

let objectArray = [
  {FullName: "Person1", PersonId: "id1"},
  {FullName: "Person2", PersonId: "id2"},
  {FullName: "Person3", PersonId: "id3"},
  {FullName: "Person4", PersonId: "id4"}
];
        
let excludeIdsArray= ["id1", "id2", "id3"];

let newObj = objectArray.reduce((arr, myObject) => {
  if(!excludeIdsArray.includes(myObject.PersonId)) {
    arr.push(myObject)
  } 
  return arr
}, [])
  

console.log(newObj)

You can use filter() to filter the array. Use new Set() to create a set object. This will make easier to check if the PersonId exists. No need to loop every filter()

let objectArray = [
  {FullName: "Person1",PersonId: "id1"},
  {FullName: "Person2",PersonId: "id2"},
  {FullName: "Person3",PersonId: "id3"},
  {FullName: "Person4",PersonId: "id4"}
];

let idsArray = ["id1", "id2", "id3"];

let idsToRemove = new Set(idsArray);
let result = objectArray.filter(o => !idsToRemove.has(o.PersonId));

console.log(result);

Another option is using includes() to test if an array includes a certain string.

let objectArray = [
  {FullName: "Person1",PersonId: "id1"},
  {FullName: "Person2",PersonId: "id2"},
  {FullName: "Person3",PersonId: "id3"},
  {FullName: "Person4",PersonId: "id4"}
];

let idsArray = ["id1", "id2", "id3"];

let result = objectArray.filter(o => !idsArray.includes(o.PersonId));

console.log(result);

Note: If you dont want a new variable, you can override the existing variable as:

objectArray = objectArray.filter(o => ...);

You can use Array.prototype.filter method in conjunction with indexOf to test if the PersonId property is found in the array of IDs to exclude - if it's not, add it to the new filteredArray. See below for example:

let objects = [{
    FullName: "Person1",
    PersonId: "id1"
  },
  {
    FullName: "Person2",
    PersonId: "id2"
  },
  {
    FullName: "Person3",
    PersonId: "id3"
  },
  {
    FullName: "Person4",
    PersonId: "id4"
  }
];

let toDelete = ["id1", "id2", "id3"];

//just use Array.prototype.filter method to remove unwanted
var filteredObjects = objects.filter(function(element) {
  return toDelete.indexOf(element.PersonId) === -1;
});

console.log(filteredObjects);

This is achieved using vanilla JavaScript. I would advise you remove linqjs from your project's codebase if this is the only thing you're using it for.

You could take Except of linq.js with an array of objects and a column parameter to exclude the unwanted PersonId.

var objectArray = [{ FullName: "Person1", PersonId: "id1" }, { FullName: "Person2", PersonId: "id2" }, { FullName: "Person3", PersonId: "id3" }, { FullName: "Person4", PersonId: "id4" }],
    idsArray = ["id1", "id2", "id3"],
    result = Enumerable
        .From(objectArray)
        .Except(
            Enumerable.From(idsArray).Select("{ PersonId: $ }"),
            "$.PersonId"
        )
        .ToArray();

console.log(result);

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