koa-flash

Flash messages for your koa application.

Installation

$ npm install koa-flash

koa-flash also depends on koa-session. You must add koa-session as a middleware prior to adding koa-flash as seen in the example:

Example

var koa = require('koa')
  , session = require('koa-session')
  , flash = require('koa-flash');
 
var app = koa();
 
app.keys = ['foo'];
app.use(session());
app.use(flash());
 
app.use(function *() {
  if (this.method === 'POST') {
    this.flash = { error: 'This is a flash error message.' };
  } else if (this.method === 'GET') {
    this.body = this.flash.error || 'No flash data.';
  }
});
 
app.listen(3000);

Semantics

Flash data when set will be saved to the user's session for exactly one more request. You can save any javascript object into this.flash (Object, Number, String, etc.). A common use case is to save an error message from a POST request when redirecting to a GET request to display the form again.

Options

Flash data is saved into this.session['koa-flash'] by default. You can change this by passing in a key option.

app.use(flash({ key: 'foo' }));

Also, you can set defaultValue instead of {}.

app.use(flash({ defaultValue: 'bar' }));

License

MIT