JS Practice — Built-in Objects

String.prototype.matchAll() — collect all matches

📖 Usage Example

const str = 'a1 b2 c3'
const matches = [...str.matchAll(/(w)(d)/g)]
matches.length   // → 3
matches[0][1]    // → 'a'

Use matchAll() with the g flag to iterate over all regex matches and access capture groups in each result.

String.prototype.matchAll()

str.matchAll(regexp) returns an iterator of all regex match results. The regex must use the g flag.

Use spread [...str.matchAll(re)] to get an array.

Challenge: Implement countMatches(str, re) that returns the number of matches.

countMatches('aababc', /a/g) // → 3

💡 Hints (2)