i have a collection with models with a property called start_time in seconds (0-60..), which is undefined if no start_time is set.
i have troubles to test if this property is 0 or null/undefined, since the handlebar #if always converts it to 0
If you are fetching the data you could use collection.parse to set a new field on the model that you could test for in your view.
YourCollection = Backbone.Collection.extend({
url: "/api/foo",
parse: function(res) {
return _.map(res, function(source) {
obj = _.clone(source);
obj.no_start = !obj.hasOwnProperty('start_time');
return obj;
});
}
});
Why not just use backbone model defaults?
YourModel = Backbone.Model.extend({
defaults : {
start_time = 'no start time'
}
});
The string should evaluate to true and any null or undefined value will be set to 'no start time' when your model is initialized.
You could do a little bit of work before calling your template: make start_time a string ('0' is true).
You could also register a helper: see boolean logic within a handlebars template.
Should give something like:
Handlebars.registerHelper('if_all', function() {
var args = [].slice.apply(arguments);
var opts = args.pop();
var fn = opts.fn;
if(!args[0] && args[0] != 0) fn = opts.inverse;
return fn(this);
});
Related
Is there a way to stop backbone validation of colelction if one model fails validation? Currently, the code does this (taken from Backbone.js 1.1.0):
for (i = 0, l = models.length; i < l; i++) {
attrs = models[i];
if (attrs instanceof Model) {
id = model = attrs;
} else {
id = attrs[targetModel.prototype.idAttribute];
}
// If a duplicate is found, prevent it from being added and
// optionally merge it into the existing model.
if (existing = this.get(id)) {
if (remove) modelMap[existing.cid] = true;
if (merge) {
attrs = attrs === model ? model.attributes : attrs;
if (options.parse) attrs = existing.parse(attrs, options);
existing.set(attrs, options);
if (sortable && !sort && existing.hasChanged(sortAttr)) sort = true;
}
models[i] = existing;
// If this is a new, valid model, push it to the `toAdd` list.
} else if (add) {
model = models[i] = this._prepareModel(attrs, options);
if (!model) continue;
toAdd.push(model);
// Listen to added models' events, and index models for lookup by
// `id` and by `cid`.
model.on('all', this._onModelEvent, this);
this._byId[model.cid] = model;
if (model.id != null) this._byId[model.id] = model;
}
if (order) order.push(existing || model);
}
So if _prepareModel returns false, which it will if a model is invalid, it will skip to next model and try to validate and add that.
I want to stop if one of the models fails validation? The app I'm working on is a tablet app and thousands of models are returned from the server (represented of course as JSON) so if the first model fails validation, I do not want all the others to be validated too, as the entire collection will be disguarded.
Any ideas how I can do this?
I would override the fetch method on your collection. Like this:
youCollection.fetch = function(options) {
options = options ? _.clone(options) : {};
if (options.parse === void 0) options.parse = true;
var success = options.success;
var collection = this;
options.success = function(resp) {
var method = options.reset ? 'reset' : 'set';
if (success) {
if (success(collection, resp, options))
collection[method](resp, options);
} else
collection[method](resp, options);
collection.trigger('sync', collection, resp, options);
};
wrapError(this, options);
return this.sync('read', this, options);
}
Here's what's happening. Focus on the line that starts with options.success =. When your server comes back with your requested models, a trigger invokes the function defined by options.success passing your models in as a parameter. In the original code, options.success looks like this:
options.success = function(resp) {
var method = options.reset ? 'reset' : 'set';
collection[method](resp, options);
if (success) success(collection, resp, options);
collection.trigger('sync', collection, resp, options);
};
What matters here that collection[method](resp, options); invokes set on the collection that called the fetch. And only then you have the option to invoke your own callback. Once collection.set is called, the validation loop on your models begins and there's nothing we could do.
We want to change that up. We want to first call our own success function. This function will run a for loop checking if each model.isValid(), and will return false as soon as one fails. If one does fail we never reach collection[method](resp, options); and set never happens.
To get a success function into your fetch call simply drop a reference to it in the options passed into fetch
yourCollection.fetch({ success: checkValidate });
I would additionally point you to Backbone.validate so that you can read about the 'invoke' trigger that gets fired when a model is invalid. That way you can handle another fetch or whatever.
I have a Backbone Model in which there are certain properties like
test_id
test_name
test_desc
test_score
Now I want to retrieve properties which are starting with "test_".
I tried with code below and its working fine.
var MyModel = Backbone.Model.extend({
getTestProperties: function(str){
// get clone of attributes to iterate over
var testProperties = {};
var attrs = _.clone(this.attributes);
_.each(attrs, function(val, key){
if(key.indexOf(str) == 0){
testProperties[key]= val;
}
}, this);
}
});
But
Is there any other way I can get these properties using underscore methods ?
Thanks
Backbone proxies some methods from Underscore on models that can help you create a more readable _.filter: _.keys and _.pick
You can then simplify your function like this :
var MyModel = Backbone.Model.extend({
getTestProperties: function (str) {
// get the keys you want
var keys = _.filter(this.keys(), function (key) {
return key.indexOf(str) === 0;
});
// and build an object
return this.pick(keys);
}
});
And a demo http://jsfiddle.net/nikoshr/5a63c/
Try something like
var attrs = _.filter(_.keys(_.clone(this.attributes)), function(attr){
return attr.indexOf("text_") === 0;
});
I want to use backbone.localStorage.js plugin in my app and here is a code sample:
Module.Vehicles = Backbone.Collection.extend({
initialize : function(options) {
this.customerId = options.customerId;
},
url : function() {
var url = App.Config.RESTPath + '/vehicle';
if(this.customerId) {
url = url + '?customerId='+this.customerId;
}
return url;
},
localStorage: new Backbone.LocalStorage("vehicles"),
model : Module.Vehicle,
parse : function(response) {
this.allVehiclesNumber = response.allVehiclesNumber;
this.customers = response.customers;
return response.vehicles;
}
});
Module.getVehicles = function(customerId) {
var result = new Module.Vehicles({
'customerId' : customerId
});
result.fetch();
return result;
};
Everything works great (collection has proper records) if I add a comment in the line:
localStorage: new Backbone.LocalStorage("vehicles"),
But if it is not commentend there are no recordsfetch.
What I missed?
BR, Tomasz.
If you check Backbone.localStorage source code, you will see that it overrides the way Backbone syncs its data : if you have a localStorage declared in you model/collection, the normal sync is discarded and replaced by a local storage.
You can alter this behavior by providing your own custom Backbone.sync. For example, this will use both versions:
Backbone.sync = function(method, model, options) {
if(model.localStorage || (model.collection && model.collection.localStorage)) {
Backbone.localSync.call(this, method, model, options);
}
return Backbone.ajaxSync.call(this, method, model, options);
};
And a Fiddle to play with http://jsfiddle.net/nikoshr/F7Hkw/
I'd like one of my getters to return a minimum value of the model's collection, is it possible to have a model getter function? Reason I need this is so I can easily have my models rendered in a template using toJSON.
Are these minimum values just defaults to fill in, if there is nothing else?
If so. you can define the defaults on the model
var model = Backbone.Model.extend({
defaults: {
attrA: 'attr a default',
attrB: 'attr b default'
}
});
Apart from the defaults you can override the get method if you need more control.
var MyModel = Backbone.Model.extend({
get: function (attr) {
if (attr === 'my_attribute')
{
return this.getMyAttribute();
}
return Backbone.Model.prototype.get.call(this, attr);
},
getMyAttribute: function() {
var result = Backbone.Model.prototype.get.call(this, attr);
if (typeof result === "undefined" || result < 0) return 0;
return result;
}
});
I have a basic application using Backbone.js that is not making PUT calls (updating model). From the front-end, I calling a models save function doesn't make a PUT call; however, if I replace it with destroy, it does make a DELETE call to the back-end. Anyone have any idea what might be the issue? The function that is not firing a PUT request is the saveTask function.
App.Views.Task = Backbone.View.extend({
template: _.template("<label>ID:</label><input type='text' id='taskId' name='id' value='<%= _id %>' disabled /><br><label>Title:</label><input type='text' id='title' name='title' value='<%= title %>' required/><br><label>Content:</label><input type='text' id='content' name='content' value='<%= content %>'/><br><button class='save'>Save</button>"),
events: {
"change input":"change",
"click .save":"saveTask"
},
render: function(eventName){
$(this.el).html(this.template(this.model.toJSON()));
//console.log(this.generateTemplate());
return this;
},
change: function(event){
var target = event.target;
console.log('changing ' + target.id + ' from: ' + target.defaultValue + ' to: ' + target.value);
change[target.name] = target.value;
this.model.set(change);*/
},
saveTask: function(){
this.model.set({
title:$("#title").val(),
content:$("#content").val()
});
if(this.model.isNew()){
App.taskList.create(this.model);
} else {
this.model.save({});
}
}
});
If your model is new, then at the time you save it it will fire a post method.
If your model however is not new and you are updating it, it will fire a PUT.
if this is not working for you it may be because your model does not have an id property, in case you are using an id with a different name, for example taskID, then in your model you have to set the idAttribute to taskID so backbone uses this property as the Id and everything will be normal.
like this:
var Task= Backbone.Model.extend({
idAttribute: "taskId"
});
here is the link to the documentation on Idattibute
http://backbonejs.org/#Model-idAttribute
also another problem could be the {} in your save call
try just
this.model.save();
instead of
this.model.save({});
I believe model is always expecting options parameter and also probably the callbacks
this.model.save(null, {
success: function (model, response) {
//
},
error: function () {
//
}
});
If you look at Backbone src, you will notice that too...
======
// Set a hash of model attributes, and sync the model to the server.
// If the server returns an attributes hash that differs, the model's
// state will be `set` again.
save: function (key, val, options) {
var attrs, method, xhr, attributes = this.attributes;
// Handle both `"key", value` and `{key: value}` -style arguments.
if (key == null || typeof key === 'object') {
attrs = key;
options = val;
} else {
(attrs = {})[key] = val;
}
options = _.extend({
validate: true
}, options);
// If we're not waiting and attributes exist, save acts as
// `set(attr).save(null, opts)` with validation. Otherwise, check if
// the model will be valid when the attributes, if any, are set.
if (attrs && !options.wait) {
if (!this.set(attrs, options)) return false;
} else {
if (!this._validate(attrs, options)) return false;
}
// Set temporary attributes if `{wait: true}`.
if (attrs && options.wait) {
this.attributes = _.extend({}, attributes, attrs);
}
// After a successful server-side save, the client is (optionally)
// updated with the server-side state.
if (options.parse === void 0) options.parse = true;
var model = this;
var success = options.success;
options.success = function (resp) {
// Ensure attributes are restored during synchronous saves.
model.attributes = attributes;
var serverAttrs = model.parse(resp, options);
if (options.wait) serverAttrs = _.extend(attrs || {}, serverAttrs);
if (_.isObject(serverAttrs) && !model.set(serverAttrs, options)) {
return false;
}
if (success) success(model, resp, options);
model.trigger('sync', model, resp, options);
};
wrapError(this, options);
method = this.isNew() ? 'create' : (options.patch ? 'patch' : 'update');
if (method === 'patch') options.attrs = attrs;
xhr = this.sync(method, this, options);
// Restore attributes.
if (attrs && options.wait) this.attributes = attributes;
return xhr;
},
In my case it fails due to validations.As i save the model it validates all the attributes of the model and the collection which i am using for listing interface doesn't required all the attributes of the model.
I was facing the same issues and search in Google and found your question and read the solution and comments.Than i realize that in updated backbone specifications it is mentioned that when model.save() executes before model requests,it first call validate and if validate succeeds than it will go ahead other wise fails, and that is the reason why it doesn't showing any network request in chrome debugger network tab.
I have write the solution for the case which i am facing,other might be facing different issues.
Backbone's sync function is what I wound up using. You have to pass in 'update' as the first parameter (the 'method' parameter).