Javascript, search multiple words and replace by themselves. Replace only 1 of them in text if found

Question

I need to replace a few words on their own in tags. For example

text text text dog text cat text text mouse.

Need to be replaced by <b>dog</b> or <b>cat</b> or <b>mouse</b> if match. I needed to replace it once . If it find word dog means to replace the only dog in <b>dog</ b> . And nothing more. Even if cat or mouse will be the text.

I have code.

var str = "dog text cat text mouse",
    reg = /dog|cat|mouse/;
str = str.replace(reg, '<b>dog</b>').

Sorry, this only replace any of matched with <b>dog</b> . Help me , please.

Answer 1

Use the g flag to make a global search instead of just replacing the first occurance.

Use parentheses in the regular expression to catch the match, and use $1 in the replacement to use what you caught.

var str = "dog text cat text mouse";
var reg = /(dog|cat|mouse)/g;
str = str.replace(reg, '<b>$1</b>')