Returns the string representation of the given value. eval'ing the output should result in a value equivalent to the input value. Many of the built-in toString methods do not satisfy this requirement.

If the given value is an [object Object] with a toString method other than Object.prototype.toString, this method is invoked with no arguments to produce the return value. This means user-defined constructor functions can provide a suitable toString method. For example:

function Point(x, y) {
  this.x = x;
  this.y = y;
}

Point.prototype.toString = function() {
  return 'new Point(' + this.x + ', ' + this.y + ')';
};

R.toString(new Point(1, 2)); //=> 'new Point(1, 2)'