snippetjavascriptTip

Pluralize a JavaScript string

Submitted by: @import:30-seconds-of-code·Mar 2, 2026·

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pluralizejavascriptstring

Problem

Tasks involving language and localization are generally more complex than they seem at first glance. One common task is pluralizing strings based on a number. While seemingly easy at first, each language has its own rules for pluralization and special cases that need to be accounted for.
Focusing on English, the rules are relatively simple: if the number is not 1, the word should be pluralized. We can write a simple function to decide whether to pluralize a word based on a number, using Math.abs(), so we can handle negative numbers as well.
The plural form of most words is simply the singular form with an _s_ added to the end. However, there are exceptions, such as _person_ becoming _people_ and _radius_ becoming _radii_. For such cases, we can easily provide a custom plural form, via an optional argument.
This works, but is a little cumbersome to use. We can improve it by using a dictionary to store the plural forms of words. This way, we can easily look up the plural form of a word based on the input number.

Solution

const isPlural = num => Math.abs(num) !== 1;

isPlural(0); // false
isPlural(1); // false
isPlural(-1); // false
isPlural(2); // true
isPlural(-2); // true

The plural form of most words is simply the singular form with an _s_ added to the end. However, there are exceptions, such as _person_ becoming _people_ and _radius_ becoming _radii_. For such cases, we can easily provide a custom plural form, via an optional argument.
This works, but is a little cumbersome to use. We can improve it by using a dictionary to store the plural forms of words. This way, we can easily look up the plural form of a word based on the input number.

Code Snippets

const isPlural = num => Math.abs(num) !== 1;

isPlural(0); // false
isPlural(1); // false
isPlural(-1); // false
isPlural(2); // true
isPlural(-2); // true

const isPlural = num => Math.abs(num) !== 1;
const simplePlural = word => `${word}s`;
const pluralize = (num, word, plural = simplePlural) =>
  isPlural(num) ? plural(word) : word;

pluralize(0, 'apple'); // 'apples'
pluralize(1, 'apple'); // 'apple'
pluralize(2, 'apple'); // 'apples'
pluralize(2, 'person', word => 'people'); // 'people'

const isPlural = num => Math.abs(num) !== 1;
const simplePlural = word => `${word}s`;
const pluralizer =
  (dictionary = {}, plural = simplePlural) =>
  (num, word) =>
    isPlural(num) ? dictionary[word] || plural(word) : word;

const PLURALS = {
  person: 'people',
  radius: 'radii',
};

const autoPluralize = pluralizer(PLURALS);
autoPluralize(0, 'apple'); // 'apples'
autoPluralize(2, 'person'); // 'people'

Context

From 30-seconds-of-code: pluralize-string

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