Use just one method many times in javascript

Question

I have a script to replace content of a document:

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

You can see i must write replace(/old1/gi, "new1").replace(/old2/gi, "new2").replace(/old3/gi, "new3").replace(/old4/gi, "new4").replace(/old5/gi, "new5"); 2 times.

How to make script works even just write above code once? like this:

var myreplace=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 = mytitle.myreplace;
var mybody=document.body.innerHTML ;
document.body.innerHTML=mybody.myreplace

Notice: old1,new1... are strings.

Possible duplicate of [Replace multiple strings with multiple other strings](https://stackoverflow.com/questions/15604140/replace-multiple-strings-with-multiple-other-strings) — Vignesh Raja, Jul 05 '18 at 04:11

CertainPerformance · Answer 1 · 2018-07-05T04:30:30.733

4

You can match old, with lookahead for a number, and replace that with new:

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

edited Jul 05 '18 at 04:30

answered Jul 05 '18 at 04:12

CertainPerformance

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No, 'old1', 'old2'... is a string – my notmypt Jul 05 '18 at 04:15
What do you mean? The `/old#/gi`s are regular expressions in your code, not strings, this should work as well – CertainPerformance Jul 05 '18 at 04:16
I mean, it's similiar `replace(/abc-(.*?)/gi, 'abc $1').replace(/def\nd/gi, 'defd')`... – my notmypt Jul 05 '18 at 04:27
@Arulraj Oops, you're right (plus lookahead for the digit), thanks – CertainPerformance Jul 05 '18 at 04:29
Thank all you guys, @Nilesh Soni helped me! – my notmypt Jul 05 '18 at 04:34

Nilesh Soni · Accepted Answer · 2018-07-05T04:36:00.227

From your question basically you need to write once. You can simply do so by writing those steps into a function and calling that function.

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);

Now if you titleEditor functionality is same as old1, old2 then you can write titleEditor as @CertainPermormance described

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

One more way you can do is adding method to String prototype

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();

Hope it's helpful

Mutating the built-in objects and prototypes is *very* bad practice - you should always prefer using standalone functions instead. — CertainPerformance, Jul 05 '18 at 04:44

score 0 · Answer 3 · answered Jul 05 '18 at 04:28

0

Write a function that takes string argument and return modified string. 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"); }

answered Jul 05 '18 at 04:28

Binara Goonawardana

1
1

Thank for your suggest! – my notmypt Jul 05 '18 at 04:35

Use just one method many times in javascript

3 Answers3