在javascript中只使用一个方法多次

var titleEditor = function(toEdit) {
    return toEdit.replace(/old1/gi, "new1")
                 .replace(/old2/gi, "new2")
                 .replace(/old3/gi, "new3")
                 .replace(/old4/gi, "new4")
                 .replace(/old5/gi, "new5");
    } 
    var mytitle = document.title ; 
    document.title = titleEditor(mytitle)
    var mybody=document.body.innerHTML;
    document.body.innerHTML= titleEditor(mybody);

var titleEditor = function(toEdit){
     return toEdit.replace(/old(\d)/gi, 'new$1')
    }

String.prototype.updateTitle = function(){
  return this.replace(/old(\d)/gi, 'new$1');
}
var mytitle = document.title ; 
document.title = mytitle.updateTitle()
var mybody=document.body.innerHTML;
document.body.innerHTML= mybody.updateTitle();

old new

const str = 'foo foo old1 bar bar old2 baz baz baz old3';
console.log(
  str.replace(/old(?=\d)/gi, 'new')
);

function replaceContent(string) { if (!string) return; return string .replace(/old1/gi, "new1") .replace(/old2/gi, "new2") .replace(/old3/gi, "new3") .replace(/old4/gi, "new4") .replace(/old5/gi, "new5"); }