Replace multiple characters in one replace call

I need to replace every instance of '_' with a space, and every instance of '#' with nothing/empty.

var string = '#Please send_an_information_pack_to_the_following_address:';

I've tried this:

string.replace('#','').replace('_', ' ');

I don't really like chaining commands like this. Is there another way to do it in one?

Use the OR operator (|):

var str = '#this #is__ __#a test###__';
str.replace(/#|_/g,''); // result: "this is a test"

You could also use a character class:

str.replace(/[#_]/g,'');

Fiddle

If you want to replace the hash with one thing and the underscore with another, then you will just have to chain. However, you could add a prototype:

String.prototype.allReplace = function(obj) {
    var retStr = this;
    for (var x in obj) {
        retStr = retStr.replace(new RegExp(x, 'g'), obj[x]);
    }
    return retStr;
};

console.log('aabbaabbcc'.allReplace({'a': 'h', 'b': 'o'}));
// console.log 'hhoohhoocc';

Why not chain, though? I see nothing wrong with that.

If you want to replace multiple characters you can call the String.prototype.replace() with the replacement argument being a function that gets called for each match. All you need is an object representing the character mapping which you will use in that function.

For example, if you want a replaced with x, b with y and c with z, you can do something like this:

var chars = {'a':'x','b':'y','c':'z'};
var s = '234abc567bbbbac';
s = s.replace(/[abc]/g, m => chars[m]);
console.log(s);

Output: 234xyz567yyyyxz

Chaining is cool, why dismiss it?

Anyway, here is another option in one replace:

string.replace(/#|_/g,function(match) {return (match=="#")?"":" ";})

The replace will choose "" if match=="#", " " if not.

[Update] For a more generic solution, you could store your replacement strings in an object:

var replaceChars={ "#":"" , "_":" " };
string.replace(/#|_/g,function(match) {return replaceChars[match];})

Specify the /g (global) flag on the regular expression to replace all matches instead of just the first:

string.replace(/_/g, ' ').replace(/#/g, '')

To replace one character with one thing and a different character with something else, you can't really get around needing two separate calls to replace. You can abstract it into a function as Doorknob did, though I would probably have it take an object with old/new as key/value pairs instead of a flat array.

I don't know if how much this will help but I wanted to remove <b> and </b> from my string

so I used

mystring.replace('<b>',' ').replace('</b>','');

so basically if you want a limited number of character to be reduced and don't waste time this will be useful.

You can just try this :

str.replace(/[.#]/g, 'replacechar');

this will replace .,- and # with your replacechar !

Second Update

I have developed the following function to use in production, perhaps it can help someone else. It's basically a loop of the native's replaceAll Javascript function, it does not make use of regex:

function replaceMultiple(text, characters){
  for (const [i, each] of characters.entries()) {
    const previousChar = Object.keys(each);
    const newChar = Object.values(each);

    text = text.replaceAll(previousChar, newChar);
  }  
  
return text
}

Usage is very simple. Here's how it would look like using OP's example:

const text = '#Please send_an_information_pack_to_the_following_address:';
const characters = [
    {
    "#":""
    },
   {
    "_":" "
    },
]

const result = replaceMultiple(text, characters);

console.log(result); //'Please send an information pack to the following address:'

Update

You can now use replaceAll natively.

Outdated Answer

Here is another version using String Prototype. Enjoy!

String.prototype.replaceAll = function(obj) {
	let finalString = '';
	let word = this;
	for (let each of word){
		for (const o in obj){
			const value = obj[o];
			if (each == o){
				each = value;
			}
		}
		finalString += each;
	}
	
	return finalString;
};

'abc'.replaceAll({'a':'x', 'b':'y'}); //"xyc"

Multiple substrings can be replaced with a simple regular expression. For example, we want to make the number (123) 456-7890 into 1234567890, we can do it as below.

var a = '(123) 456-7890';
var b = a.replace(/[() -]/g, '');
console.log(b); // results 1234567890

We can pass the substrings to be replaced between [] and the string to be used instead should be passed as the second parameter to the replace function.

Please try:

• replace multi string

  var str = "http://www.abc.xyz.com"; str = str.replace(/http:|www|.com/g, ''); //str is "//.abc.xyz"

• replace multi chars

  var str = "a.b.c.d,e,f,g,h"; str = str.replace(/[.,]/g, ''); //str is "abcdefgh";

Good luck!

Here's a simple way to do it without RegEx.
You can prototype and/or cache things as desired.

// Example: translate( 'faded', 'abcdef', '123456' ) returns '61454'
function translate( s, sFrom, sTo ){
    for ( var out = '', i = 0; i < s.length; i++ ){
        out += sTo.charAt( sFrom.indexOf( s.charAt(i) ));
    }
    return out;
}

You could also try this :

function replaceStr(str, find, replace) {
    for (var i = 0; i < find.length; i++) {
        str = str.replace(new RegExp(find[i], 'gi'), replace[i]);
    }
    return str;
}

var text = "#here_is_the_one#";
var find = ["#","_"];
var replace = ['',' '];
text = replaceStr(text, find, replace);
console.log(text);

find refers to the text to be found and replace to the text to be replaced with

This will be replacing case insensitive characters. To do otherway just change the Regex flags as required. Eg: for case sensitive replace :

new RegExp(find[i], 'g')

You can also pass a RegExp object to the replace method like

var regexUnderscore = new RegExp("_", "g"); //indicates global match
var regexHash = new RegExp("#", "g");

string.replace(regexHash, "").replace(regexUnderscore, " ");

Javascript RegExp

yourstring = '#Please send_an_information_pack_to_the_following_address:';

replace '#' with '' and replace '_' with a space

var newstring1 = yourstring.split('#').join('');
var newstring2 = newstring1.split('_').join(' ');

newstring2 is your result

For replacing with nothing, tckmn's answer is the best.

If you need to replace with specific strings corresponding to the matches, here's a variation on Voicu's and Christophe's answers that avoids duplicating what's being matched, so that you don't have to remember to add new matches in two places:

const replacements = {
  '’': "'",
  '“': '"',
  '”': '"',
  '—': '---',
  '–': '--',
};
const replacement_regex = new RegExp(Object
  .keys(replacements)
  // escape any regex literals found in the replacement keys:
  .map(e => e.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'))
  .join('|')
, 'g');
return text.replace(replacement_regex, e => replacements[e]);

This works for Yiddish other character's like NEKUDES

var string = "נׂקֹוַדֹּוֶת";


var string_norm = string.replace(/[ְֱֲֳִֵֶַָֹֹּׁׂ]/g, '');
document.getElementById("demo").innerHTML = (string_norm);

Here is a "safe HTML" function using a 'reduce' multiple replacement function (this function applies each replacement to the entire string, so dependencies among replacements are significant).

// Test:
document.write(SafeHTML('<div>\n\
    x</div>'));

function SafeHTML(str)
	{
	const replacements = [
		{'&':'&amp;'},
		{'<':'&lt;'},
		{'>':'&gt;'},
		{'"':'&quot;'},
		{"'":'&apos;'},
		{'`':'&grave;'},
		{'\n':'<br>'},
		{' ':'&nbsp;'}
		];
	return replaceManyStr(replacements,str);
	} // HTMLToSafeHTML

function replaceManyStr(replacements,str)
	{
	return replacements.reduce((accum,t) => accum.replace(new RegExp(Object.keys(t)[0],'g'),t[Object.keys(t)[0]]),str);
	}

String.prototype.replaceAll=function(obj,keydata='key'){
 const keys=keydata.split('key');
return Object.entries(obj).reduce((a,[key,val])=> a.replace(new RegExp(`${keys[0]}${key}${keys[1]}`,'g'),val),this)
}

const data='hids dv sdc sd {yathin} {ok}'
console.log(data.replaceAll({yathin:12,ok:'hi'},'{key}'))

Not sure why nobody has offered this solution yet but I find it works quite nicely:

var string = '#Please send_an_information_pack_to_the_following_address:'
var placeholders = [
    "_": " ",
    "#": ""
]

for(var placeholder in placeholders){
	while(string.indexOf(placeholder) > -1) {
		string = string.replace(placeholder, placeholders[placeholder])
	}
}

You can add as any placeholders as you like without having to update your function. Simple!

One function and one prototype function.

String.prototype.replaceAll = function (search, replacement) {
    var target = this;
    return target.replace(new RegExp(search, 'gi'), replacement);
};


            var map = {
                '&': 'and ',
                '[?]': '',
                '/': '',
                '#': '',
                // '|': '#65 ',
                // '[\]': '#66 ',
                // '\\': '#67 ',
                // '^': '#68 ',
                '[?&]': ''
            };


             var map2 = [
                {'&': 'and '},
                {'[?]': ''},
                {'/': ''},
                {'#': ''},                
                {'[?&]': ''}
            ];

            name = replaceAll2(name, map2);
            name = replaceAll(name, map);


    function replaceAll2(str, map) {            
        return replaceManyStr(map, str);
    }  

    function replaceManyStr(replacements, str) {
        return replacements.reduce((accum, t) => accum.replace(new RegExp(Object.keys(t)[0], 'g'), t[Object.keys(t)[0]]), str);
    }