myString.replace( VARIABLE, "") ...... but globally

Question

How can I use a variable to remove all instances of a substring from a string? (to remove, I'm thinking the best way is to replace, with nothing, globally... right?)

if I have these 2 strings,

myString = "This sentence is an example sentence."
oldWord = " sentence"

then something like this

myString.replace(oldWord, "");

only replaces the first instance of the variable in the string.

but if I add the global g like this myString.replace(/oldWord/g, ""); it doesn't work, because it thinks oldWord, in this case, is the substring, not a variable. How can I do this with the variable?

possible duplicate of [How do you pass a variable to a Regular Expression JavaScript?](http://stackoverflow.com/questions/494035/how-do-you-pass-a-variable-to-a-regular-expression-javascript) — fxp, Nov 06 '13 at 07:47

score 94 · Accepted Answer · edited Oct 24 '17 at 13:50

94

Well, you can use this:

var reg = new RegExp(oldWord, "g");
myString.replace(reg, "");

or simply:

myString.replace(new RegExp(oldWord, "g"), "");

edited Oct 24 '17 at 13:50

Steffan

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answered Apr 13 '12 at 06:17

Derek 朕會功夫

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3

Boom: `var oldWord = '\\';` – Camilo Martin Dec 07 '14 at 03:35

score 12 · Answer 2 · answered Apr 13 '12 at 06:19

12

You have to use the constructor rather than the literal syntax when passing variables. Stick with the literal syntax for literal strings to avoid confusing escape syntax.

var oldWordRegEx = new RegExp(oldWord,'g');

myString.replace(oldWordRegEx,"");

answered Apr 13 '12 at 06:19

Erik Reppen

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Woot! Is that copying from me? – Derek 朕會功夫 Apr 13 '12 at 06:34
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I just type slower and offer more advice. – Erik Reppen Apr 13 '12 at 06:37
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Sigh... always a bridesmaid never an answer. – Erik Reppen Apr 13 '12 at 06:48

score 7 · Answer 3 · answered Jan 23 '17 at 20:57

No need to use a regular expression here: split the string around matches of the substring you want to remove, then join the remaining parts together:

myString.split(oldWord).join('')

In the OP's example:

var myString = "This sentence is an example sentence.";
var oldWord = " sentence";
console.log(myString.split(oldWord).join(''));

score -2 · Answer 4 · answered Feb 19 '15 at 14:08

-2

According to the docs at MDN, you can do this:

var re = /apples/gi;
var str = 'Apples are round, and apples are juicy.';
var newstr = str.replace(re, 'oranges');
console.log(newstr);  // oranges are round, and oranges are juicy.

where /gi tells it to do a global replace, ignoring case.

answered Feb 19 '15 at 14:08

MatthewS

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This does not answer the question. – Derek 朕會功夫 Jul 03 '15 at 00:40
The question is about replacing the content of a variable – bra_racing Oct 22 '18 at 07:22

myString.replace( VARIABLE, "") ...... but globally

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