Sweet 16 Javascript Hacks and Tips To Optimize Performance & Save time

JavaScript or JS helps implement complex things on web pages. Many of the developers know the importance of an minified Javascript file but few are aware of an Optimized Javascript code.

An optimized code is a combination of smartly programmed logics and small hacks to optimize performance, speed and save time.

Here are sweet 16 JS hacks and tips for developers for optimizing Javascript to improve JS performance and improve execution time without affecting server resources.

1. Use Array Filter

It is a small hack to filter out bucket of elements from the array pool. This method creates an array filled with all array elements that pass a test (provided as a function). According to requirement create a callback function for non-required elements.

In below example the bucket elements are null and are ready to get filtered out.

Example:

schema = ["hi","ihaveboyfriend",null, null, "goodbye"]
schema = schema.filter(function(n) {
 return n
 });
Output: ["hi","ihaveboyfriend", "goodbye"]

This hack will save some time and lines of codes for developers.

2. Using String replace function to replace all the values

The String.replace() function allows you to replace strings using String and Regex.

Basically this function replaces the string at its first occurrence. But to replace all using replaceAll() function, use /g at the end of a Regex:

Example:

var string = "login login"; 
console.log(string.replace("in", "out")); // "logout login" 
console.log(string.replace(/in/g, "out")); //"logout logout"

3. Use breakpoints and Console for Debugging

With the help of breakpoints or debugging points you can set multiple barriers to rectify source of error at every barrier.

Press F11 for next call function and f8 to resume script execution.

You can also check what dynamic values are generated by a function, using console and can check output on different values.

#javascript #programming

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Buddha Community

Reform: Form Objects Decoupled From Models In Ruby

Reform

Form objects decoupled from your models.

Reform gives you a form object with validations and nested setup of models. It is completely framework-agnostic and doesn't care about your database.

Although reform can be used in any Ruby framework, it comes with Rails support, works with simple_form and other form gems, allows nesting forms to implement has_one and has_many relationships, can compose a form from multiple objects and gives you coercion.

Full Documentation

Reform is part of the Trailblazer framework. Full documentation is available on the project site.

Reform 2.2

Temporary note: Reform 2.2 does not automatically load Rails files anymore (e.g. ActiveModel::Validations). You need the reform-rails gem, see Installation.

Defining Forms

Forms are defined in separate classes. Often, these classes partially map to a model.

class AlbumForm < Reform::Form
  property :title
  validates :title, presence: true
end

Fields are declared using ::property. Validations work exactly as you know it from Rails or other frameworks. Note that validations no longer go into the model.

The API

Forms have a ridiculously simple API with only a handful of public methods.

1. #initialize always requires a model that the form represents.
2. #validate(params) updates the form's fields with the input data (only the form, not the model) and then runs all validations. The return value is the boolean result of the validations.
3. #errors returns validation messages in a classic ActiveModel style.
4. #sync writes form data back to the model. This will only use setter methods on the model(s).
5. #save (optional) will call #save on the model and nested models. Note that this implies a #sync call.
6. #prepopulate! (optional) will run pre-population hooks to "fill out" your form before rendering.

In addition to the main API, forms expose accessors to the defined properties. This is used for rendering or manual operations.

Setup

In your controller or operation you create a form instance and pass in the models you want to work on.

class AlbumsController
  def new
    @form = AlbumForm.new(Album.new)
  end

This will also work as an editing form with an existing album.

def edit
  @form = AlbumForm.new(Album.find(1))
end

Reform will read property values from the model in setup. In our example, the AlbumForm will call album.title to populate the title field.

Rendering Forms

Your @form is now ready to be rendered, either do it yourself or use something like Rails' #form_for, simple_form or formtastic.

= form_for @form do |f|
  = f.input :title

Nested forms and collections can be easily rendered with fields_for, etc. Note that you no longer pass the model to the form builder, but the Reform instance.

Optionally, you might want to use the #prepopulate! method to pre-populate fields and prepare the form for rendering.

Validation

After form submission, you need to validate the input.

class SongsController
  def create
    @form = SongForm.new(Song.new)

    #=> params: {song: {title: "Rio", length: "366"}}

    if @form.validate(params[:song])

The #validate method first updates the values of the form - the underlying model is still treated as immutuable and remains unchanged. It then runs all validations you provided in the form.

It's the only entry point for updating the form. This is per design, as separating writing and validation doesn't make sense for a form.

This allows rendering the form after validate with the data that has been submitted. However, don't get confused, the model's values are still the old, original values and are only changed after a #save or #sync operation.

Syncing Back

After validation, you have two choices: either call #save and let Reform sort out the rest. Or call #sync, which will write all the properties back to the model. In a nested form, this works recursively, of course.

It's then up to you what to do with the updated models - they're still unsaved.

Saving Forms

The easiest way to save the data is to call #save on the form.

if @form.validate(params[:song])
  @form.save  #=> populates album with incoming data
              #   by calling @form.album.title=.
else
  # handle validation errors.
end

This will sync the data to the model and then call album.save.

Sometimes, you need to do saving manually.

Default values

Reform allows default values to be provided for properties.

class AlbumForm < Reform::Form
  property :price_in_cents, default: 9_95
end

Saving Forms Manually

Calling #save with a block will provide a nested hash of the form's properties and values. This does not call #save on the models and allows you to implement the saving yourself.

The block parameter is a nested hash of the form input.

  @form.save do |hash|
    hash      #=> {title: "Greatest Hits"}
    Album.create(hash)
  end

You can always access the form's model. This is helpful when you were using populators to set up objects when validating.

  @form.save do |hash|
    album = @form.model

    album.update_attributes(hash[:album])
  end

Nesting

Reform provides support for nested objects. Let's say the Album model keeps some associations.

class Album < ActiveRecord::Base
  has_one  :artist
  has_many :songs
end

The implementation details do not really matter here, as long as your album exposes readers and writes like Album#artist and Album#songs, this allows you to define nested forms.

class AlbumForm < Reform::Form
  property :title
  validates :title, presence: true

  property :artist do
    property :full_name
    validates :full_name, presence: true
  end

  collection :songs do
    property :name
  end
end

You can also reuse an existing form from elsewhere using :form.

property :artist, form: ArtistForm

Nested Setup

Reform will wrap defined nested objects in their own forms. This happens automatically when instantiating the form.

album.songs #=> [<Song name:"Run To The Hills">]

form = AlbumForm.new(album)
form.songs[0] #=> <SongForm model: <Song name:"Run To The Hills">>
form.songs[0].name #=> "Run To The Hills"

Nested Rendering

When rendering a nested form you can use the form's readers to access the nested forms.

= text_field :title,         @form.title
= text_field "artist[name]", @form.artist.name

Or use something like #fields_for in a Rails environment.

= form_for @form do |f|
  = f.text_field :title

  = f.fields_for :artist do |a|
    = a.text_field :name

Nested Processing

validate will assign values to the nested forms. sync and save work analogue to the non-nested form, just in a recursive way.

The block form of #save would give you the following data.

@form.save do |nested|
  nested #=> {title:  "Greatest Hits",
         #    artist: {name: "Duran Duran"},
         #    songs: [{title: "Hungry Like The Wolf"},
         #            {title: "Last Chance On The Stairways"}]
         #   }
  end

The manual saving with block is not encouraged. You should rather check the Disposable docs to find out how to implement your manual tweak with the official API.

Populating Forms

Very often, you need to give Reform some information how to create or find nested objects when validateing. This directive is called populator and documented here.

Installation

Add this line to your Gemfile:

gem "reform"

Reform works fine with Rails 3.1-5.0. However, inheritance of validations with ActiveModel::Validations is broken in Rails 3.2 and 4.0.

Since Reform 2.2, you have to add the reform-rails gem to your Gemfile to automatically load ActiveModel/Rails files.

gem "reform-rails"

Since Reform 2.0 you need to specify which validation backend you want to use (unless you're in a Rails environment where ActiveModel will be used).

To use ActiveModel (not recommended because very out-dated).

require "reform/form/active_model/validations"
Reform::Form.class_eval do
  include Reform::Form::ActiveModel::Validations
end

To use dry-validation (recommended).

require "reform/form/dry"
Reform::Form.class_eval do
  feature Reform::Form::Dry
end

Put this in an initializer or on top of your script.

Compositions

Reform allows to map multiple models to one form. The complete documentation is here, however, this is how it works.

class AlbumForm < Reform::Form
  include Composition

  property :id,    on: :album
  property :title, on: :album
  property :songs, on: :cd
  property :cd_id, on: :cd, from: :id
end

When initializing a composition, you have to pass a hash that contains the composees.

AlbumForm.new(album: album, cd: CD.find(1))

More

Reform comes many more optional features, like hash fields, coercion, virtual fields, and so on. Check the full documentation here.

Reform is part of the Trailblazer project. Please buy my book to support the development and learn everything about Reform - there's two chapters dedicated to Reform!

Security And Strong_parameters

By explicitly defining the form layout using ::property there is no more need for protecting from unwanted input. strong_parameter or attr_accessible become obsolete. Reform will simply ignore undefined incoming parameters.

This is not Reform 1.x!

Temporary note: This is the README and API for Reform 2. On the public API, only a few tiny things have changed. Here are the Reform 1.2 docs.

Anyway, please upgrade and report problems and do not simply assume that we will magically find out what needs to get fixed. When in trouble, join us on Gitter.

Full documentation for Reform is available online, or support us and grab the Trailblazer book. There is an Upgrading Guide to help you migrate through versions.

Attributions!!!

Great thanks to Blake Education for giving us the freedom and time to develop this project in 2013 while working on their project.

---

Author: trailblazer
Source code: https://github.com/trailblazer/reform
License:  MIT license

#ruby  #ruby-on-rails

Sweet 16 Javascript Hacks and Tips To Optimize Performance & Save time

JavaScript or JS helps implement complex things on web pages. Many of the developers know the importance of an minified Javascript file but few are aware of an Optimized Javascript code.

An optimized code is a combination of smartly programmed logics and small hacks to optimize performance, speed and save time.

Here are sweet 16 JS hacks and tips for developers for optimizing Javascript to improve JS performance and improve execution time without affecting server resources.

1. Use Array Filter

It is a small hack to filter out bucket of elements from the array pool. This method creates an array filled with all array elements that pass a test (provided as a function). According to requirement create a callback function for non-required elements.

In below example the bucket elements are null and are ready to get filtered out.

Example:

schema = ["hi","ihaveboyfriend",null, null, "goodbye"]
schema = schema.filter(function(n) {
 return n
 });
Output: ["hi","ihaveboyfriend", "goodbye"]

This hack will save some time and lines of codes for developers.

2. Using String replace function to replace all the values

The String.replace() function allows you to replace strings using String and Regex.

Basically this function replaces the string at its first occurrence. But to replace all using replaceAll() function, use /g at the end of a Regex:

Example:

var string = "login login"; 
console.log(string.replace("in", "out")); // "logout login" 
console.log(string.replace(/in/g, "out")); //"logout logout"

3. Use breakpoints and Console for Debugging

With the help of breakpoints or debugging points you can set multiple barriers to rectify source of error at every barrier.

Press F11 for next call function and f8 to resume script execution.

You can also check what dynamic values are generated by a function, using console and can check output on different values.

#javascript #programming

The essential JavaScript concepts that you should understand

As a JavaScript developer of any level, you need to understand its foundational concepts and some of the new ideas that help us developing code. In this article, we are going to review 16 basic concepts. So without further ado, let’s get to it.

#javascript-interview #javascript-development #javascript-fundamental #javascript #javascript-tips

7 Simple JavaScript Tips for Optimizing Your Code

I know you care about optimizing your code but sometimes you don’t know how to do it.

Imagine every piece of your code is well optimized, the performance would be great and you can easily investigate your code if having any issue.

So, without any further ado, let’s dive right into the 7 simple JavaScript tips below.

#programming-tips #javascript #programming #javascript-tips

Performance Optimization Techniques

Performance is an integral part of the Application design and plays a vital role in the success of your product/application. This is Part-2 of the performance optimization articles series. Performance optimization considerations for an enterprise-level application are discussed as part of Part-1.

Before delving into performance optimization techniques, let us discuss the factors that impact the performance of an application. Below are the most critical factors that impact the performance from my view.

Factors That Impact the Performance of the Application

• Stuffing home/start page with lots of functionality
• Making a huge number of API calls/ Loading large JS bundles as part of the initial load of the applications
• Ineffective JavaScript modules loading strategies (Not effectively using lazy loading)
• Using large size images without any image optimization/compression
• Preloading all the data in the browser instead of considering user preferences/user actions
• Not adopting CDN to deliver the content to the global audience (at least static content/files)
• Invalid network/tool configurations
• Using the same website/ APIs for Mobile and Desktop
• Introducing additional tools only in the production environment

Performance Optimization Techniques

This section gives you an overview of the various techniques that can be employed at various levels of your application. At a global level, below are few areas

User Interface

Below are a few of the core best practices to consider as part of the user interface design and development

User Interface Design Best Practices

• Consider server-side rendering for your home/landing page if it stuffed with too much functionality
• Load data on demand always
• Enabling paging when dealing with large datasets

#javascript #performance #css #best practices #performance optimization