Replace multiple strings with multiple other strings

Specific Solution

You can use a function to replace each one.

var str = "I have a cat, a dog, and a goat.";var mapObj = {   cat:"dog",   dog:"goat",   goat:"cat"};str = str.replace(/cat|dog|goat/gi, function(matched){  return mapObj[matched];});

jsfiddle example

Generalizing it

If you want to dynamically maintain the regex and just add future exchanges to the map, you can do this

new RegExp(Object.keys(mapObj).join("|"),"gi"); 

to generate the regex. So then it would look like this

var mapObj = {cat:"dog",dog:"goat",goat:"cat"};var re = new RegExp(Object.keys(mapObj).join("|"),"gi");str = str.replace(re, function(matched){  return mapObj[matched];});

And to add or change any more replacements you could just edit the map. 

fiddle with dynamic regex

Making it Reusable

If you want this to be a general pattern you could pull this out to a function like this

function replaceAll(str,mapObj){    var re = new RegExp(Object.keys(mapObj).join("|"),"gi");    return str.replace(re, function(matched){        return mapObj[matched.toLowerCase()];    });}

So then you could just pass the str and a map of the replacements you want to the function and it would return the transformed string.

fiddle with function

To ensure Object.keys works in older browsers, add a polyfill eg from MDN or Es5.

As an answer to:

looking for an up-to-date answer

If you are using "words" as in your current example, you might extend the answer of Ben McCormick using a non capture group and add word boundaries \b at the left and at the right to prevent partial matches.

\b(?:cathy|cat|catch)\b

• \b A word boundary to prevent a partial match
• (?: Non capture group
  • cathy|cat|catch match one of the alternatives
• ) Close non capture group
• \b A word boundary to prevent a partial match

Example for the original question:

let str = "I have a cat, a dog, and a goat.";const mapObj = {  cat: "dog",  dog: "goat",  goat: "cat"};str = str.replace(/\b(?:cat|dog|goat)\b/gi, matched => mapObj[matched]);console.log(str);