用于在两组字符之间提取文本的正则表达式(Javascript)

为什么不直接做呢

var toExtract = "start-extractThis-234";
var extracted = null;
var split = toExtract.split("-");
if(split.length === 3){
   extracted = split[1];
}

string = "start-extractThis-234"

console.log( string.match( '-(.*)-' )[1] );

//returns extractThis

^.+?-(.+?)-\d+$