What is set.size in TypeScript?

Overview

A set is a data structure that stores a collection of unordered and unique entries that are without duplicates. It is different from arrays because, unlike arrays, sets store unique values.

The size property of a set returns the set's size. The size is the number of entries it has.

Syntax

set.size

Return value

The value returned is an integer value that represents the number of entries a set contains.

Example

// create some sets
let names = new Set<string>(["Theodore", "David", "John", "Janme"])
let evenNumbers = new Set<number>([2, 4, 6, 8, 10, 12])
let booleanValues = new Set<boolean>([true, false])
let countries = new Set<string>(["Nigeria", "Brazil", "Ghana", "Egypt", "Germany"])
let nothing = new Set<null>()
// log their sizes to the console
console.log(names.size)          // 4
console.log(evenNumbers.size)    // 6
console.log(booleanValues.size)  // 2
console.log(countries.size)      // 5
console.log(nothing.size)        // 0

Explanation

  • Lines 2–6: We create some sets in TypeScript.
  • Lines 9–13: We log out the sizes of the sets we have created, to the console.

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