#hof-behaviour-session

HOF Behaviour for reading and writing to the session

##Usage

###With mixwith.js

const mix = require('mixwith').mix;
const Session = require('hof-behaviour-session');
const BaseController = require('hof-form-controller');

class MyController extends mix(BaseController).with(Session) {
  ...
}

MyController now extends hof-form-controller and has hof-behaviour-session functionality mixed in.

##Functionality

This mixin extends hof-form-controller by persisting the form data to the sessionModel - assuming the session-model middleware has been applied.

The following form controller methods are used:

• getValues(req, res, cb) - calls callback with null and a map of all items in the sessionModel, extended with errorValues - to persist entered values on current step if validation fails
• saveValues(req, res, cb) - Called on success. Sets all step fields in req.form.values to the sessionModel, unsets errorValues.
• getErrors(req) - returns all errors for fields on the current step (req.form.options.fields), excluding redirects. Set to req.form.errors in hof-form-controller.
• setErrors(err, req) - called on validation error(s). Sets the current step field values as errorValues in sessionModel to be used in getValues. Sets errors to sessionModel - a map of field-name: error to be used in getErrors.
• locals(req, res) - Extends the result of super.locals with baseUrl (req.baseUrl) and nextPage (the result of this.getNextStep(req, res)).
• missingPrereqHandler(req, res) - Error handler called when a MISSING_PREREQ error is thrown from the check-progress middleware. This occurs if a step is visited out of sequence. This error handler causes the user to be redirected to the last completed step, or the first step if none have been completed.
• errorHandler(err, req, res, next) - checks if err.code is MISSING_PREREQ, if so calls missingPrereqHandler, if not calls super to hand over to parent error handler.