(js)正則 replace

var str = '-abb-aaab-';

console.log('original: ', str);
console.log('------------------------');

console.log(str.replace(/(a)(b)/g, '<$&>')); => -<ab>b-aa<ab>-

console.log(str.replace(/(a)(b)/g,'<$2>')); => -<b>b-aa<b>-

console.log(str.replace(/(a)(b)/g,'<$1>')); => -<a>b-aa<a>-

console.log('------------------------');


console.log(str.replace(/(a)|(b)/g, '<$&>')); => -<a><b><b>-<a><a><a><b>-

console.log(str.replace(/(a)|(b)/g,'<$2>')); => -<><b><b>-<><><><b>-

console.log(str.replace(/(a)|(b)/g,'<$1>')); => -<a><><>-<a><a><a><>-

--------------------------------------------------------------------------------

console.dir(str.match(/(a)|(b)/g)); => [ 'a', 'b', 'b', 'a', 'a', 'a', 'b' ]