frequency

Counts the frequency of each element in an array, returning an object with the occurrences.

Syntax

frequency(arr: any[]): Record<PropertyKey, number>

Parameters

Name	Type	Description
arr	number[]	Array of numbers to analyze.

Return

Type	Description
object	An object mapping each value to its frequency.

Example

frequency(['a', 'b', 'a', 'c', 'b', 'a']); // { a: 3, b: 2, c: 1 }
frequency([1, 2, 2, 3]); // { '1': 1, '2': 2, '3': 1 }

Notes

• Throws TypeError if the argument is not an array.
• Useful for data analysis and simple statistics.

References

• MDN: Array.prototype.reduce()