Count the occurrences of a character in a string

JavaScript version

const countOccurrences = (str, char) => [...str].reduce((a, v) => (v === char ? a + 1 : a), 0);

// Or
const countOccurrences = (str, char) => str.split('').reduce((a, v) => (v === char ? a + 1 : a), 0);

// Or
const countOccurrences = (str, char) => [...str].filter((item) => item === char).length;

// Or
const countOccurrences = (str, char) => str.split('').filter((item) => item === char).length;

TypeScript version

const countOccurrences = (str: string, char: string): number => [...str].reduce((a, v) => (v === char ? a + 1 : a), 0);

// Or
const countOccurrences = (str: string, char: string): number => str.split('').reduce((a, v) => (v === char ? a + 1 : a), 0);

// Or
const countOccurrences = (str: string, char: string): number => [...str].filter((item) => item === char).length;

// Or
const countOccurrences = (str: string, char: string): number => str.split('').filter((item) => item === char).length;

Examples

countOccurrences('a.b.c.d.e', '.'); // 4