SOURCE

let str = '123abc'

function testMatch(str, regex){
    console.log(regex + '')
    for(let _match of str.match(regex)){
        console.log(_match)
    }
    console.log('----------------------')
}

testMatch('123abc', /(\d+)(?:abc)/g)
testMatch('123abc,asdasa11223abcasdasd', /(\d+)(abc)/g)
testMatch('123abc,asdasa11223abcasdasd', /(\d+)(abc)/y)
testMatch('123abc,asdasa11223abcasdasd', /(\d+)(abc)/m)
testMatch('123abc,asdasa11223abcasdasd', /(\d+)(abc)/)
testMatch('123abc,asdasa11223abcasdasd', /(\d+)(?=abc)/)
testMatch('123abc,asdasa11223abcasdasd', /(\d+)(?:abc)/)
testMatch('123abc', /((\d+)(abc))/g)