Backbone Validate is sending a request when validation fails - validation

Question

According to the backbone documentation about validation it states:
If validate returns an error, set and save will not continue, and the
model attributes will not be modified.
So the way I read that set or save should never run if the validation fails. But that is not the results I am getting. Even when validation fails it still sends the POST/PUT request. Am I reading the docs wrong or doing something incorrect in my code?
Here is my relevant code:
https://gist.github.com/80f6ef0099fbe96025dc
App.Models.Test = Backbone.Model.extend(
urlRoot: '/api/test'
validate: (attrs) ->
errors = []
if attrs.to is ''
errors.push
name: "to"
field: "js-to"
message: "You must enter a to address"
if attrs.subject is ''
errors.push
name: "subject"
field: "js-subject"
message: "You must enter a subject"
# Return our errors array if it isn't empty
errors if errors.length > 0
)
App.Views.Details = Backbone.View.extend(
initialize: ->
#model.bind "error", #error, this
events:
"click #js-save": "saveItem"
saveItem: (e) ->
e.preventDefault()
# Set the model then save it.
#model.set
subject: $("#js-subject").val()
message: $("#js-message").val()
mailbox_id: $("#js-from").val()
to: $("#js-to").val()
cc: $("#js-cc").val()
bcc: $("#js-bcc").val()
tags: App.Helpers.tagsToObject $('#js-tags').val()
scope: $('#js-scope').val()
attachments: attachments
#model.save null,
success: (model, response) =>
App.Helpers.showAlert "Success!", "Saved Successfully", "alert-success"
#next()
error: (model, response) ->
App.Helpers.showAlert "Error", "An error occurred while trying to save this item", "alert-error"
# Show the errors based on validation failure.
error: (model, error) ->
App.Helpers.displayValidationErrors error

Answer 1

You do this to save your model:
#model.save null,
success: -> ...
error: -> ...
That null is the source of your trouble, use {} and things will start behaving better; if you combine your #model.set and #model.save calls, things will be even better:
attrs =
subject: $("#js-subject").val()
#...
#model.save attrs,
success: -> ...
error: -> ...
A save call looks like this:
save model.save([attributes], [options])
[...]
The attributes hash (as in set) should contain the attributes you'd like to change
So passing a null for attributes means that you want to save the model as it is.
When you save a model, the validation is mostly left up to set, the code looks like this:
if (attrs && !this.set(attrs, options.wait ? silentOptions : options)) {
return false;
}
Your attrs will be null so set will not be called; however, if you let save handle your set, you will get the behavior you're after. If you passed the wait: true option, save would manually run the validation on the passed attributes:
if (options.wait) {
if (!this._validate(attrs, options)) return false;
...
}
The internal _validate method is a wrapper for validate that does some bookkeeping and error handling. You're not using wait: true so this doesn't apply to you but I thought it was worth mentioning anyway.
Consider a simple example with a model whose validate always fails. If you say this:
#model.on 'error', #error
#model.save attrs,
success: -> console.log 'AJAX success'
error: -> console.log 'AJAX error'
then #error will be called because save will end up calling set with some attributes and set will call validate. Demo: http://jsfiddle.net/ambiguous/HHQ2N/1/
But, if you say:
#model.save null, ...
the null will cause the set call to be skipped. Demo: http://jsfiddle.net/ambiguous/6pX2e/ (the AJAX here will fail).
Your #model.set call right before #model.save should be triggering your error handler but if you don't check what #model.set returns, execution will blindly continue on to the save call and talk to your server.
In summary, you have three things going on here:
You're not calling save they way you should be.
You're ignoring the #model.set return value and losing your chance to trap the validation errors.
Backbone's argument handling for save(null, ...) could be better but I don't know if it is worth the effort to handle a strange way of calling it.
You should combine your set/save pair into just a save or check what set returns.