Javascript replace regex don't work

Question

I have problem with regexp for replace html code in string. I had tried online regexp tester with match, but something causes that I canť replace. ${ProductEAN} is what I want replace. Any idea what is wrong?

The string is here:

<label for="ProductEAN" id="ProductEAN" class="col-sm-3 control-label">${ProductEAN}</label>

Javascript code:

let strToReplace = 'ProductEAN';
let reg = new RegExp('/(\$\{'+strToReplace+'\})/','g')
        str.replace(reg,'some text');

Make sure to mark the best answer as accepted if it helped you. That way it doesn't show up as unanswered. — rvighne, Jul 15 '16 at 20:29

score 2 · Answer 1 · answered Jul 15 '16 at 19:34

2

The RegExp constructor doesn't need slashes (/.../) around the expression, that is only for regex literals. And when you backslash-escape characters, they are escaped in the string passed to the constructor, but pass unescaped to the actual regex expression. They need to be double-escaped. So, change the line to this:

let reg = new RegExp('\\$\\{'+strToReplace+'\\}','g');

answered Jul 15 '16 at 19:34

rvighne

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This work for me,thanks for the explanation. – robertnovak Jul 15 '16 at 19:40

Nina Scholz · Answer 2 · 2016-07-15T19:46:39.593

0

You need proper escaping the backslashes

reg = new RegExp('\\$\\{' + strToReplace + '\\}', 'g');

and an assignment for the replaced string.

newString = str.replace(reg,'some text');

var element = document.getElementById('ProductEAN'),
    strToReplace = 'ProductEAN',
    reg = new RegExp('\\$\\{' + strToReplace + '\\}', 'g');

element.innerHTML = element.innerHTML.replace(reg,'some text');

<label for="ProductEAN" id="ProductEAN" class="col-sm-3 control-label">${ProductEAN}</label>

edited Jul 15 '16 at 19:46

answered Jul 15 '16 at 19:30

Nina Scholz

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That is not the issue. The string is not actually properly replaced. – rvighne Jul 15 '16 at 19:31

score 0 · Answer 3 · answered Jul 15 '16 at 19:31

0

This should do it:

var str = '<label for="ProductEAN" id="ProductEAN" class="col-sm-3 control-label">${ProductEAN}</label>';
var strToReplace = 'ProductEAN';
var reg = new RegExp('(\\${'+strToReplace+'})','g')
str.replace(reg,'some text');

answered Jul 15 '16 at 19:31

tpdietz

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raphael75 · Answer 4 · 2016-07-15T19:39:05.177

-1

Try this:

new RegExp('\$\{' + strToReplace + '\}','g')

When invoked with RegExp, you don't have to put the /'s in. You also shouldn't need the ()'s.

More info here: http://www.javascriptkit.com/jsref/regexp.shtml

Also, you can get rid of the let's. They aren't needed.

edited Jul 15 '16 at 19:39

answered Jul 15 '16 at 19:36

raphael75

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Why would you not need the brackets? – Cjmarkham Jul 15 '16 at 19:39
1

"Also, you can get rid of the let's. They aren't needed." What do you mean? You have no idea of his context here, so he could possibly want the `let`s. – Colin DeClue Jul 15 '16 at 19:39
The let statement declares a block scope local variable, it is needed – Cjmarkham Jul 15 '16 at 19:40
I just tested it and it worked. The braces are there, I didn't remove them. I only removed the () and the /'s. – raphael75 Jul 15 '16 at 19:46

Javascript replace regex don't work

4 Answers4