array-of-object-query

array-of-object-query is a simple JavaScript library that makes working with arrays of objects easier. It has some methods to help you filter, sort, group, and summarize data. Use this library to make handling complex data structures simple and efficient.

Installation

To install this package, simply run the following command with npm:

$ npm install array-of-object-query

Usage

To use the custom array methods provided by the array-of-object-query package, just import the methods:

import arrayQuires from "array-of-object-query";

Apply the Methods

After import the method, you can apply the methods directly to your arrays of objects. Here's an example using the where method:

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 34, occupation: "Designer" },
  { name: "Charlie", age: 25, occupation: "Teacher" },
];

// Example usage of where method
const engineers = people.where("occupation", "Engineer");
console.log(engineers);
// Output: [{ name: 'Alice', age: 28, occupation: 'Engineer' }]

Available Methods

All of the available methods are provided below

• where
• whereIn
• select
• pluck
• orderBy
• first
• last
• min
• max
• take
• sum
• average
• groupBy
• unique
• distinct

where(key, value)

Description

Filters the array based on key-value pairs.

Parameters

• key: The key to filter objects by.
• value: The value to filter objects against.

Returns

• An array of objects that match the specified key-value pair.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
];

const engineers = people.where("occupation", "Engineer");
// Output: [{ name: "Alice", age: 28, occupation: "Engineer" }]

const teacher = people.where("occupation", "Teacher").where("age", 30);
// Output: [{ name: "Charlie", age: 30, occupation: "Teacher" }]

whereIn(key, values)

Description

Filters the array where a key's value is in an array of values.

Parameters

• key: The key to filter by.
• values: An array of values to match against the key.

Returns

• An array containing objects where the specified key's value matches any of the provided values.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
];

const filtered = people.whereIn("age", [25, 28]);
// Output: [{ name: "Alice", age: 28, occupation: "Engineer" },{ name: "Bob", age: 25, occupation: "Designer" }]

select(key)

Description

Creates a new array with objects containing only the specified key.

Parameters

• ...keys: One or more keys to select from each object.

Returns

• An array of objects with only the specified key and its corresponding values.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
];

const names = people.select("name");
// Output: [{ name: "Alice" }, { name: "Bob" }, { name: "Charlie" }]

const namesAndAges = people.select("name", "age");
// Output: [{ name: "Alice", age: 28 }, { name: "Bob", age: 25 }, { name: "Charlie", age: 30 }]

pluck(...keys)

Description

Returns arrays of values for specified keys from each object in the array.

Parameters

• ...keys: One or more keys to pluck values from each object.

Returns

• An array of arrays containing values corresponding to the specified keys from each object.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
];

const pluckedValues = people.pluck("name", "age");
// Output: [["Alice", "Bob", "Charlie"], [28, 25, 30]]

orderBy(key, order='asc')

Description

Sorts the array of objects based on a specified key and order.

Parameters

• key: The key to sort by.
• order (optional): Sorting order, either 'asc' (default) or 'desc'.

Returns

• The sorted array of objects.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
];

const sortedByNameAsc = people.orderBy("name");
// Output: [{ name: "Alice", age: 28, occupation: "Engineer" }, { name: "Bob", age: 25, occupation: "Designer" }, { name: "Charlie", age: 30, occupation: "Teacher" }]

const sortedByAgeDesc = people.orderBy("age", "desc");
// Output: [{ name: "Charlie", age: 30, occupation: "Teacher" }, { name: "Alice", age: 28, occupation: "Engineer" }, { name: "Bob", age: 25, occupation: "Designer" }]

first()

Description

Retrieves the first element of the array.

Parameters

• None

Returns

• The first element of the array, or undefined if the array is empty.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
];

const firstPerson = people.first();
// Output: { name: "Alice", age: 28, occupation: "Engineer" }

last()

Description

Retrieves the last element of the array.

Parameters

• None

Returns

• The last element of the array, or undefined if the array is empty.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
];

const lastPerson = people.last();
// Output: { name: "Charlie", age: 30, occupation: "Teacher" }

min(key)

Description

Finds the minimum value of a specified numeric property across all objects in the array.

Parameters

• key: The key representing the numeric property to find the minimum value for.

Returns

• The minimum value of the specified numeric property, or undefined if the array is empty or if the property values are not numeric.

Example

const people = [
  { name: "Alice", age: 28 },
  { name: "Bob", age: 25 },
  { name: "Charlie", age: 30 },
];

const minAge = people.min("age");
// Output: 25

max(key)

Description

Finds the maximum value of a specified numeric property across all objects in the array.

Parameters

• key: The key representing the numeric property to find the maximum value for.

Returns

• The maximum value of the specified numeric property, or undefined if the array is empty or if the property values are not numeric.

Example

const people = [
  { name: "Alice", age: 28 },
  { name: "Bob", age: 25 },
  { name: "Charlie", age: 30 },
];

const maxAge = people.max("age");
// Output: 30

take(count)

Description

Retrieves a specified number of elements from the beginning of the array.

Parameters

• count: The number of elements to retrieve from the beginning of the array.

Returns

• An array containing the specified number of elements from the beginning of the original array.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
];

const firstTwoPeople = people.take(2);
// Output: [{ name: "Alice", age: 28, occupation: "Engineer" }, { name: "Bob", age: 25, occupation: "Designer" }]

sum(key)

Description

Calculates the sum of a specified numeric property across all objects in the array.

Parameters

• key: The key representing the numeric property to calculate the sum for.

Returns

• The sum of the specified numeric property, or 0 if the array is empty or if the property values are not numeric.

Example

const expenses = [
  { item: "Rent", amount: 1000 },
  { item: "Groceries", amount: 300 },
  { item: "Utilities", amount: 200 },
];

const totalExpenses = expenses.sum("amount");
// Output: 1500

average(key)

Description

Calculates the average value of a specified numeric property across all objects in the array.

Parameters

• key: The key representing the numeric property to calculate the average for.

Returns

• The average value of the specified numeric property, or undefined if the array is empty or if the property values are not numeric.

Example

const scores = [
  { student: "Alice", score: 85 },
  { student: "Bob", score: 90 },
  { student: "Charlie", score: 75 },
];

const averageScore = scores.average("score");
// Output: 83.33

groupBy(key)

Description

Groups elements of the array based on a specified key.

Parameters

• key: The key by which to group the elements.

Returns

• An object where keys are unique values of the specified key, and values are arrays of objects that share the same key value.

Example

const people = [
  { name: "Alice", age: 28, occupation: "Engineer" },
  { name: "Bob", age: 25, occupation: "Designer" },
  { name: "Charlie", age: 30, occupation: "Teacher" },
  { name: "David", age: 28, occupation: "Developer" },
];

const groupedByAge = people.groupBy("age");
// Output:
// {
//   '25': [{ name: "Bob", age: 25, occupation: "Designer" }],
//   '28': [
//     { name: "Alice", age: 28, occupation: "Engineer" },
//     { name: "David", age: 28, occupation: "Developer" }
//   ],
//   '30': [{ name: "Charlie", age: 30, occupation: "Teacher" }]
// }

unique(key)

Description

Returns an array of unique objects based on a specified key.

Parameters

• key: The key representing the property to determine uniqueness.

Returns

• An array containing unique objects based on the specified key.

Example

const items = [
  { id: 1, name: "Apple" },
  { id: 2, name: "Orange" },
  { id: 1, name: "Apple" },
  { id: 3, name: "Banana" },
];

const uniqueItems = items.unique("id");
// Output: [{ id: 1, name: "Apple" }, { id: 2, name: "Orange" }, { id: 3, name: "Banana" }]

distinct(key)

Description

Returns an array of distinct values of a specified property across all objects in the array.

Parameters

• key: The key representing the property to retrieve distinct values for.

Returns

• An array containing distinct values of the specified property.

Example

const items = [
  { id: 1, name: "Apple" },
  { id: 2, name: "Orange" },
  { id: 1, name: "Apple" },
  { id: 3, name: "Banana" },
];

const distinctIds = items.distinct("id");
// Output: [1, 2, 3]

License

array-of-object-query is created by Fahim Muntasir . Released under the MIT license.