regex.test( )

[thjttk]

const regex = /a/g

console.log(regex.test('abca')) // true
console.log(regex.test('abca')) // true
console.log(regex.test('abca')) // false 🤣
console.log(regex.test('abca')) // true

[thjttk]

// recommend
console.log('abca'.match(regex)) // ['a', 'a']
console.log('efg'.match(regex)) // null

regex.test with g flag is supposed to be called many times.
refer to https://2ality.com/2013/08/regexp-g.html