包含一个l和三个w的正则表达式匹配字符串

var str =
`wwww
lwlw
lwww
wlww
wwlw
wwwl
llll`;
//this function checks if the length of string after replace is equal to length
var replChLen = (str, ch, length) => 
    str.replace( new RegExp( ch, "g" ), "" ).length == length;

//filter out the matches
var output = str.split( "\n" ) //split by line-break
   .filter( s => //iterate to filter
      replChLen(s, "l", s.length - 1) //check if after replacing l, length is reduced by 1
        && replChLen(s, "w", s.length - 3) ); //check if after replacing w, length is reduced by 3
console.log( output );

var string = 
`wwww
lwlw
lwww
wlww
wwlw
wwwl
llll`;
var pattern = ["lwww","wlww","wwlw","wwwl"];

var vals = string.split(/\s/).filter(function(row) {
  row = row.trim();
  return pattern.indexOf(row)!=-1;
})
console.log(vals)

var string = 
`wwww
lwlw
lwww
wlww
wwlw
wwwl
llll`;

var vals = string.split(/\s/).filter(function(row) {
  return "lwww"=== row.trim().split("").sort().join("");
})
console.log(vals)