javascript - Best/efficent way to remember last function result -

i got used using bind remember last result of function , keep track able use last result next result. instance concat or join last string new string without using outer variables:

function remstr(outstr){    return function c(laststr,newstr){      if(!newstr)return laststr;      var = laststr+newstr;      return c.bind(null,all);    }.bind(null,outstr);  }  var str = remstr('stack'); str = str('over'); str = str('flow'); str(); // stackoverflow 

the problem want call remstr several times , bind came play. can done better or differently, maybe turns out 1 case approach fulfills task better remstr?

if understand intention correctly, how using closure?

function remstr(outstr) {    return function c(newstr) {      if (!newstr) return outstr;      outstr += newstr;      return c;    }  }    var str = remstr('stack');  str = str('over');  str = str('flow');  str(); // stackoverflow

as mentioned tomalak in comments, javascript strings immutable, if intend use large or many strings, want buffer them in array.

function remstr(outstr) {    var buffer = [outstr || ''];    return function c(newstr) {      if (!newstr) return buffer.join('');      buffer.push(newstr);      return c;    }  }    var str = remstr('stack');  str = str('over');  str = str('flow');  str(); // stackoverflow