code: func formatJSStructTagVal(jsTag string) string {
  	for i, r := range jsTag {
  		ok := unicode.IsLetter(r) || (i != 0 && unicode.IsNumber(r)) || r == '$' || r == '_'
  		if !ok {
  			// Saw an invalid JavaScript identifier character,
  			// so use bracket notation.
  			return `["` + template.JSEscapeString(jsTag) + `"]`
  		}
  	}
  	// Safe to use dot notation without any escaping.
  	return "." + jsTag
  }
docs: // formatJSStructTagVal returns JavaScript code for accessing an object's property
  // identified by jsTag. It prefers the dot notation over the bracket notation when
  // possible, since the dot notation produces slightly smaller output.
  //
  // For example:
  //
  // 	"my_name" -> ".my_name"
  // 	"my name" -> `["my name"]`
  //
  // For more information about JavaScript property accessors and identifiers, see
  // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_Accessors and
  // https://developer.mozilla.org/en-US/docs/Glossary/Identifier.
  //