before = function before(str, re) {
  return str.replace(re, function (match) {
    var id = randomize();
    cache$1[id] = match;
    return '__ID' + id + '__';
  });
}
Replace tokens in `str` with a temporary, heuristic placeholder.

```js
tokens.before('{a\\,b}');
//=> '{__ID1__}'
```

@param  {String} `str`
@return {String} String with placeholders.
@api public