使用正则表达式提取 substring

Question

I am trying to make a parser for PGN-file moves. I would like to extract a substring from the total text-input starting from move 1.

This is an example piece of a PGN file:

PGN-file

I tried to extract the moves in a substring using indexOf() by a regex.

This is my attempt:

 function extractMoves(){ const pgn = '[Date "2013.11.12"] 1.Nf3 d5 2.g3 g6'; // Sample PGN. const firstMove = /1\.([ah]|[NBRQK])/; // First move regex. const moves = pgn.substring(pgn.indexOf(firstMove)); return moves; } console.log(extractMoves());

This is the expected output:

1.Nf3 d5 2.g3 g6

Answer 1

indexOf doesn't work with regex. Use search instead.

It gives the expected output now:

function extractMoves(){
    const pgn = '[Date "2013.11.12"] 1.Nf3 d5 2.g3 g6'
    const firstMove = /1\.([a-h]|[NBRQK])/;
    const moves = pgn.substring(pgn.search(firstMove));
    return moves;
}
console.log(extractMoves());