Replace strings via regexp by groups in Javascript

Question

I would like to replace many terms using regexp with a single call, is it possible? In the example below I want to replace all spaces and ö chars to _ and - respectively.

Pattern: ( +)|(ö+)

Source string: Abc dfö/ab.ai dois ö

Replace pattern: $1_$2-

Current result: Abc _-df_ö-/ab.ai _-dois _-_ö-

Expected result: Abc_df-/ab.ai_dois_-

Thanks.

Wiktor Stribiżew · Accepted Answer · 2015-10-30 15:27:56Z

2

Use a callback function to check which group "worked" and replace accordingly:

var re = /( +)|(ö+)/g; 
var str = 'Abc dfö/ab.ai dois ö';
var result = str.replace(re, function (m, g1, g2) {
    return g1 ? "_" : "-";
});
document.getElementById("r").innerHTML = result;

<div id="r"/>

The second argument in .replace() accepts a function.

A function to be invoked to create the new substring (to put in place of the substring received from parameter #1).

See more details on the callback function parameters in the Specifying a function as a parameter section.

UPDATE

You may map the symbols (since you are searching for single symbols) to the replacement symbols, and specify them all in 1 regex. Then, in the callback function, you can get the necessary value using the first character from the matched text.

var rx = / +|ö+|ë+|ü+/g;
str = "Abc dfö/ab.ai dois ööö üüü";
console.log(str);
map = { 
    " ": "_", 
    "ö": "-", 
    "ü": "+", 
    "ë": "^"
};
result = str.replace(rx, function (match) {
    return map[match[0]]; }
);
console.log(result);
// Abc dfö/ab.ai dois ööö üüü => Abc_df-/ab.ai_dois_-_+

edited Oct 30, 2015 at 15:27

answered Oct 30, 2015 at 14:00

Wiktor Stribiżew

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4 Comments

Marcelo Idemax Over a year ago

Thanks @stribizhev but I need a solution more generic in case of I have for example /( +)|(ö+)|(ä+)|(ë+)|(ü+)|(etc...+)/g

Wiktor Stribiżew Over a year ago

XY problem? That is not good. Anyway, you will have 2 choices: either use the callback specifying the necessary amount of capturing groups, or use chained replace() methods. You cannot specify multiple literal replacements in the replacement pattern.

Marcelo Idemax Over a year ago

yes @stribizhev... I was trying to avoid that approach so looks like that will be the way. thanks and upped :)

Peter Seliger Over a year ago

one could change the OR connected pattern in a way that its remaining capturing group can be used as key of a map of surrogate/replacement characters. ``` var regX = /( |ö)+/g, str = "Abc dfö/ab.ai dois ö", map = { " ": "_", "ö": "-", }, result = str.replace(regX, function (match, $1) { return map[$1]; }) ; console.log("str, result : ", str, result);```

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