So I built a small wrapper around String.prototype.replace to give the syntax and power of javascript regular expressions (and, optionally, javascript functions):

https://github.com/ariabuckles/jsed

Or to install:

    npm install -g @ariabuckles/jsed

You can use it pretty similarly to `sed`:

    echo "this is a test" | jsed '\w+' 'word:$&'
    > word:this word:is word:a word:test

     echo "1 2 3 4" | jsed '/\d+/g' '(num) => num%2 == 0 ? "even" : "odd"'