Storing your application's flash messages in a cookie means you can cache the whole page.
## Ruby/Sinatra
```ruby
def flash(key, value)
fail "Invalid key '#{key}'" unless [ :info, :error ].include?(key)
response.set_cookie "flash_#{key}", value: I18n.t(value), path: '/'
end
```
Put the code in a helper or controller.
## Javascript
```javascript
var Flash;
Flash = (function() {
function Flash(flash_holder, cookie_prefix) {
this.flash_holder = flash_holder;
this.cookie_prefix = cookie_prefix;
if (this.flash_holder == null) {
this.flash_holder = '#flash';
}
if (this.cookie_prefix == null) {
this.cookie_prefix = 'flash_';
}
}
Flash.prototype.show = function() {
var i, key, len, name, ref, results, value;
ref = ['info', 'error'];
results = [];
for (i = 0, len = ref.length; i < len; i++) {
key = ref[i];
name = this.cookie_prefix + key;
value = Cookies.get(name);
if (value) {
$(this.flash_holder).attr('class', name).html(value).show('fast');
results.push(Cookies.remove(name));
} else {
results.push(void 0);
}
}
return results;
};
return Flash;
})();
$(function() {
new Flash().show();
return new Flash('#flash_holder', 'cookie_prefix').show();
});
```
## HTML
```javascript
```
## CSS
```css
#flash {
display: none
}
.flash_info {
color: darkgreen
}
.flash_error {
color: darkred
}
```
Usage
-----
In your controller:
```javascript
get '/' do
flash :info, 'login.failed'
end
```
## Dependencies
* [js-cookie](https://github.com/js-cookie/js-cookie)
* I18n gem