javascript replace with regexp?

Question

I want to write a javascript function to format message, this is my code:

pattern = "{0},{1}";
args = ["hello", "world"];

pattern.replace(/\{(\d+)\}/g, args["$1"*1]); //$1 stands for \d+, multiply 1 to convert it to a number

I want the result is hello,world, but it is undefined,undefined. so how to change it to make it correct ?

"$1"*1 returns NaN. Which is not an index on the args array — CodingIntrigue
– CodingIntrigue, Commented Apr 2, 2014 at 7:09

CD.. · Accepted Answer · 2014-04-02 07:08:54Z

3

Like this:

pattern.replace(/\{(\d+)\}/g, function($0, $1){ 
   return args[$1];
});

answered Apr 2, 2014 at 7:08

CD..

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2 Comments

hiway Over a year ago

what does $0, $1 mean?

CodingIntrigue Over a year ago

@hiway $0 is just the matched string, $1 being the first match parameter. See the MDN docs for replace: developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…

Jaykumar Patel · Accepted Answer · 2014-04-02 07:14:45Z

0

Check this demo jsFiddle

Regexp Patten

/\{(\d+)\},\{(\d+)\}/g

JavaScript

 pattern = "{0},{1}";
 args = ["hello", "world"];

 pattern.replace(/\{(\d+)\},\{(\d+)\}/g, args);
 //console.log(pattern.replace(/\{(\d+)\},\{(\d+)\}/g, args));

Console Result

hello,world

answered Apr 2, 2014 at 7:14

Jaykumar Patel

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1 Comment

CodingIntrigue Over a year ago

But this is hardcoded to two variables. @CD..'s answer handles an infinite amount of parameters

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