simple dynamic string templating for js that follows the syntax of es6 template literals

template-string.es6

const rxTemplateSubst = /\\?\${([^}]*)}/g;
function template(str, substitutions) {
    if(!str) return str;
    return str.replace(rxTemplateSubst, (token, name) => { 
        if(token[0] === '\\') return token.substr(1);
        return String(substitutions[name]); 
    });
}

// simple replacements...
console.log(
    template("here is a ${what}, please send your comments to ${who}.", { what: "thingy", who: "mom" }));

// escapes...
console.log(
    template("this one here is \\${escaped}, so it won't be replaced", {}));


// numbered/positional replacements...
function format(str, ...substitutions) {
    return template(str, substitutions);
}
console.log(
    format("here is a ${0} that I want you to ${1} ${2} times", "comment", "read", 5));