40 Tips That Will Change Your Coding Skills Forever

In this summary, I list some of the things that have helped me in my career. It reads fast, but applying them well can take a lifetime. I have been developing applications for almost 15 years, and still, sometimes, I have to stop and think in the essential parts of this profession.
Take the code and break down big pieces of code into small functions.
If by the time you leave work you haven’t solved the problem. Turn off the computer and leave it for the next day. Don’t think about the problem anymore.
YAGNI principle: don’t codify more than you’ve been asked to. Don’t anticipate the future, and just create something that works as soon as possible. Code only the necessary parts to solve the current problem.
You don’t need to know everything, nor all the existing frameworks. The most significant thing is to have a good base. Know the language in depth before starting with a Framework and learn fundamental things like the SOLID principles or how to write clean code.

#development-tips #coding #solid-principles #development #javascript

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40 Tips That Will Change Your Coding Skills Forever
Tyrique  Littel

Tyrique Littel

1604008800

Static Code Analysis: What It Is? How to Use It?

Static code analysis refers to the technique of approximating the runtime behavior of a program. In other words, it is the process of predicting the output of a program without actually executing it.

Lately, however, the term “Static Code Analysis” is more commonly used to refer to one of the applications of this technique rather than the technique itself — program comprehension — understanding the program and detecting issues in it (anything from syntax errors to type mismatches, performance hogs likely bugs, security loopholes, etc.). This is the usage we’d be referring to throughout this post.

“The refinement of techniques for the prompt discovery of error serves as well as any other as a hallmark of what we mean by science.”

  • J. Robert Oppenheimer

Outline

We cover a lot of ground in this post. The aim is to build an understanding of static code analysis and to equip you with the basic theory, and the right tools so that you can write analyzers on your own.

We start our journey with laying down the essential parts of the pipeline which a compiler follows to understand what a piece of code does. We learn where to tap points in this pipeline to plug in our analyzers and extract meaningful information. In the latter half, we get our feet wet, and write four such static analyzers, completely from scratch, in Python.

Note that although the ideas here are discussed in light of Python, static code analyzers across all programming languages are carved out along similar lines. We chose Python because of the availability of an easy to use ast module, and wide adoption of the language itself.

How does it all work?

Before a computer can finally “understand” and execute a piece of code, it goes through a series of complicated transformations:

static analysis workflow

As you can see in the diagram (go ahead, zoom it!), the static analyzers feed on the output of these stages. To be able to better understand the static analysis techniques, let’s look at each of these steps in some more detail:

Scanning

The first thing that a compiler does when trying to understand a piece of code is to break it down into smaller chunks, also known as tokens. Tokens are akin to what words are in a language.

A token might consist of either a single character, like (, or literals (like integers, strings, e.g., 7Bob, etc.), or reserved keywords of that language (e.g, def in Python). Characters which do not contribute towards the semantics of a program, like trailing whitespace, comments, etc. are often discarded by the scanner.

Python provides the tokenize module in its standard library to let you play around with tokens:

Python

1

import io

2

import tokenize

3

4

code = b"color = input('Enter your favourite color: ')"

5

6

for token in tokenize.tokenize(io.BytesIO(code).readline):

7

    print(token)

Python

1

TokenInfo(type=62 (ENCODING),  string='utf-8')

2

TokenInfo(type=1  (NAME),      string='color')

3

TokenInfo(type=54 (OP),        string='=')

4

TokenInfo(type=1  (NAME),      string='input')

5

TokenInfo(type=54 (OP),        string='(')

6

TokenInfo(type=3  (STRING),    string="'Enter your favourite color: '")

7

TokenInfo(type=54 (OP),        string=')')

8

TokenInfo(type=4  (NEWLINE),   string='')

9

TokenInfo(type=0  (ENDMARKER), string='')

(Note that for the sake of readability, I’ve omitted a few columns from the result above — metadata like starting index, ending index, a copy of the line on which a token occurs, etc.)

#code quality #code review #static analysis #static code analysis #code analysis #static analysis tools #code review tips #static code analyzer #static code analysis tool #static analyzer

40 Tips That Will Change Your Coding Skills Forever

In this summary, I list some of the things that have helped me in my career. It reads fast, but applying them well can take a lifetime. I have been developing applications for almost 15 years, and still, sometimes, I have to stop and think in the essential parts of this profession.
Take the code and break down big pieces of code into small functions.
If by the time you leave work you haven’t solved the problem. Turn off the computer and leave it for the next day. Don’t think about the problem anymore.
YAGNI principle: don’t codify more than you’ve been asked to. Don’t anticipate the future, and just create something that works as soon as possible. Code only the necessary parts to solve the current problem.
You don’t need to know everything, nor all the existing frameworks. The most significant thing is to have a good base. Know the language in depth before starting with a Framework and learn fundamental things like the SOLID principles or how to write clean code.

#development-tips #coding #solid-principles #development #javascript

Martin  Soit

Martin Soit

1591849679

Top 40 Tips that will Change Your Coding Skills forever

In this summary, I list some of the things that have helped me in my career. It reads fast, but applying them well can take a lifetime. I have been developing applications for almost 15 years, and still, sometimes, I have to stop and think in the essential parts of this profession.

#development #development tips #coding #javascript

Samanta  Moore

Samanta Moore

1621137960

Guidelines for Java Code Reviews

Get a jump-start on your next code review session with this list.

Having another pair of eyes scan your code is always useful and helps you spot mistakes before you break production. You need not be an expert to review someone’s code. Some experience with the programming language and a review checklist should help you get started. We’ve put together a list of things you should keep in mind when you’re reviewing Java code. Read on!

1. Follow Java Code Conventions

2. Replace Imperative Code With Lambdas and Streams

3. Beware of the NullPointerException

4. Directly Assigning References From Client Code to a Field

5. Handle Exceptions With Care

#java #code quality #java tutorial #code analysis #code reviews #code review tips #code analysis tools #java tutorial for beginners #java code review

Annie  Emard

Annie Emard

1653075360

HAML Lint: Tool For Writing Clean and Consistent HAML

HAML-Lint

haml-lint is a tool to help keep your HAML files clean and readable. In addition to HAML-specific style and lint checks, it integrates with RuboCop to bring its powerful static analysis tools to your HAML documents.

You can run haml-lint manually from the command line, or integrate it into your SCM hooks.

Requirements

  • Ruby 2.4+
  • HAML 4.0+

Installation

gem install haml_lint

If you'd rather install haml-lint using bundler, don't require it in your Gemfile:

gem 'haml_lint', require: false

Then you can still use haml-lint from the command line, but its source code won't be auto-loaded inside your application.

Usage

Run haml-lint from the command line by passing in a directory (or multiple directories) to recursively scan:

haml-lint app/views/

You can also specify a list of files explicitly:

haml-lint app/**/*.html.haml

haml-lint will output any problems with your HAML, including the offending filename and line number.

File Encoding

haml-lint assumes all files are encoded in UTF-8.

Command Line Flags

Command Line FlagDescription
--auto-gen-configGenerate a configuration file acting as a TODO list
--auto-gen-exclude-limitNumber of failures to allow in the TODO list before the entire rule is excluded
-c/--configSpecify which configuration file to use
-e/--excludeExclude one or more files from being linted
-i/--include-linterSpecify which linters you specifically want to run
-x/--exclude-linterSpecify which linters you don't want to run
-r/--reporterSpecify which reporter you want to use to generate the output
-p/--parallelRun linters in parallel using available CPUs
--fail-fastSpecify whether to fail after the first file with lint
--fail-levelSpecify the minimum severity (warning or error) for which the lint should fail
--[no-]colorWhether to output in color
--[no-]summaryWhether to output a summary in the default reporter
--show-lintersShow all registered linters
--show-reportersDisplay available reporters
-h/--helpShow command line flag documentation
-v/--versionShow haml-lint version
-V/--verbose-versionShow haml-lint, haml, and ruby version information

Configuration

haml-lint will automatically recognize and load any file with the name .haml-lint.yml as a configuration file. It loads the configuration based on the directory haml-lint is being run from, ascending until a configuration file is found. Any configuration loaded is automatically merged with the default configuration (see config/default.yml).

Here's an example configuration file:

linters:
  ImplicitDiv:
    enabled: false
    severity: error

  LineLength:
    max: 100

All linters have an enabled option which can be true or false, which controls whether the linter is run, along with linter-specific options. The defaults are defined in config/default.yml.

Linter Options

OptionDescription
enabledIf false, this linter will never be run. This takes precedence over any other option.
includeList of files or glob patterns to scope this linter to. This narrows down any files specified via the command line.
excludeList of files or glob patterns to exclude from this linter. This excludes any files specified via the command line or already filtered via the include option.
severityThe severity of the linter. External tools consuming haml-lint output can use this to determine whether to warn or error based on the lints reported.

Global File Exclusion

The exclude global configuration option allows you to specify a list of files or glob patterns to exclude from all linters. This is useful for ignoring third-party code that you don't maintain or care to lint. You can specify a single string or a list of strings for this option.

Skipping Frontmatter

Some static blog generators such as Jekyll include leading frontmatter to the template for their own tracking purposes. haml-lint allows you to ignore these headers by specifying the skip_frontmatter option in your .haml-lint.yml configuration:

skip_frontmatter: true

Inheriting from Other Configuration Files

The inherits_from global configuration option allows you to specify an inheritance chain for a configuration file. It accepts either a scalar value of a single file name or a vector of multiple files to inherit from. The inherited files are resolved in a first in, first out order and with "last one wins" precedence. For example:

inherits_from:
  - .shared_haml-lint.yml
  - .personal_haml-lint.yml

First, the default configuration is loaded. Then the .shared_haml-lint.yml configuration is loaded, followed by .personal_haml-lint.yml. Each of these overwrite each other in the event of a collision in configuration value. Once the inheritance chain is resolved, the base configuration is loaded and applies its rules to overwrite any in the intermediate configuration.

Lastly, in order to match your RuboCop configuration style, you can also use the inherit_from directive, which is an alias for inherits_from.

Linters

» Linters Documentation

haml-lint is an opinionated tool that helps you enforce a consistent style in your HAML files. As an opinionated tool, we've had to make calls about what we think are the "best" style conventions, even when there are often reasonable arguments for more than one possible style. While all of our choices have a rational basis, we think that the opinions themselves are less important than the fact that haml-lint provides us with an automated and low-cost means of enforcing consistency.

Custom Linters

Add the following to your configuration file:

require:
  - './relative/path/to/my_first_linter.rb'
  - 'absolute/path/to/my_second_linter.rb'

The files that are referenced by this config should have the following structure:

module HamlLint
  # MyFirstLinter is the name of the linter in this example, but it can be anything
  class Linter::MyFirstLinter < Linter
    include LinterRegistry

    def visit_tag
      return unless node.tag_name == 'div'
      record_lint(node, "You're not allowed divs!")
    end
  end
end

For more information on the different types on HAML node, please look through the HAML parser code: https://github.com/haml/haml/blob/master/lib/haml/parser.rb

Keep in mind that by default your linter will be disabled by default. So you will need to enable it in your configuration file to have it run.

Disabling Linters within Source Code

One or more individual linters can be disabled locally in a file by adding a directive comment. These comments look like the following:

-# haml-lint:disable AltText, LineLength
[...]
-# haml-lint:enable AltText, LineLength

You can disable all linters for a section with the following:

-# haml-lint:disable all

Directive Scope

A directive will disable the given linters for the scope of the block. This scope is inherited by child elements and sibling elements that come after the comment. For example:

-# haml-lint:disable AltText
#content
  %img#will-not-show-lint-1{ src: "will-not-show-lint-1.png" }
  -# haml-lint:enable AltText
  %img#will-show-lint-1{ src: "will-show-lint-1.png" }
  .sidebar
    %img#will-show-lint-2{ src: "will-show-lint-2.png" }
%img#will-not-show-lint-2{ src: "will-not-show-lint-2.png" }

The #will-not-show-lint-1 image on line 2 will not raise an AltText lint because of the directive on line 1. Since that directive is at the top level of the tree, it applies everywhere.

However, on line 4, the directive enables the AltText linter for the remainder of the #content element's content. This means that the #will-show-lint-1 image on line 5 will raise an AltText lint because it is a sibling of the enabling directive that appears later in the #content element. Likewise, the #will-show-lint-2 image on line 7 will raise an AltText lint because it is a child of a sibling of the enabling directive.

Lastly, the #will-not-show-lint-2 image on line 8 will not raise an AltText lint because the enabling directive on line 4 exists in a separate element and is not a sibling of the it.

Directive Precedence

If there are multiple directives for the same linter in an element, the last directive wins. For example:

-# haml-lint:enable AltText
%p Hello, world!
-# haml-lint:disable AltText
%img#will-not-show-lint{ src: "will-not-show-lint.png" }

There are two conflicting directives for the AltText linter. The first one enables it, but the second one disables it. Since the disable directive came later, the #will-not-show-lint element will not raise an AltText lint.

You can use this functionality to selectively enable directives within a file by first using the haml-lint:disable all directive to disable all linters in the file, then selectively using haml-lint:enable to enable linters one at a time.

Onboarding Onto a Preexisting Project

Adding a new linter into a project that wasn't previously using one can be a daunting task. To help ease the pain of starting to use Haml-Lint, you can generate a configuration file that will exclude all linters from reporting lint in files that currently have lint. This gives you something similar to a to-do list where the violations that you had when you started using Haml-Lint are listed for you to whittle away, but ensuring that any views you create going forward are properly linted.

To use this functionality, call Haml-Lint like:

haml-lint --auto-gen-config

This will generate a .haml-lint_todo.yml file that contains all existing lint as exclusions. You can then add inherits_from: .haml-lint_todo.yml to your .haml-lint.yml configuration file to ensure these exclusions are used whenever you call haml-lint.

By default, any rules with more than 15 violations will be disabled in the todo-file. You can increase this limit with the auto-gen-exclude-limit option:

haml-lint --auto-gen-config --auto-gen-exclude-limit 100

Editor Integration

Vim

If you use vim, you can have haml-lint automatically run against your HAML files after saving by using the Syntastic plugin. If you already have the plugin, just add let g:syntastic_haml_checkers = ['haml_lint'] to your .vimrc.

Vim 8 / Neovim

If you use vim 8+ or Neovim, you can have haml-lint automatically run against your HAML files as you type by using the Asynchronous Lint Engine (ALE) plugin. ALE will automatically lint your HAML files if it detects haml-lint in your PATH.

Sublime Text 3

If you use SublimeLinter 3 with Sublime Text 3 you can install the SublimeLinter-haml-lint plugin using Package Control.

Atom

If you use atom, you can install the linter-haml plugin.

TextMate 2

If you use TextMate 2, you can install the Haml-Lint.tmbundle bundle.

Visual Studio Code

If you use Visual Studio Code, you can install the Haml Lint extension

Git Integration

If you'd like to integrate haml-lint into your Git workflow, check out our Git hook manager, overcommit.

Rake Integration

To execute haml-lint via a Rake task, make sure you have rake included in your gem path (e.g. via Gemfile) add the following to your Rakefile:

require 'haml_lint/rake_task'

HamlLint::RakeTask.new

By default, when you execute rake haml_lint, the above configuration is equivalent to running haml-lint ., which will lint all .haml files in the current directory and its descendants.

You can customize your task by writing:

require 'haml_lint/rake_task'

HamlLint::RakeTask.new do |t|
  t.config = 'custom/config.yml'
  t.files = ['app/views', 'custom/*.haml']
  t.quiet = true # Don't display output from haml-lint to STDOUT
end

You can also use this custom configuration with a set of files specified via the command line:

# Single quotes prevent shell glob expansion
rake 'haml_lint[app/views, custom/*.haml]'

Files specified in this manner take precedence over the task's files attribute.

Documentation

Code documentation is generated with YARD and hosted by RubyDoc.info.

Contributing

We love getting feedback with or without pull requests. If you do add a new feature, please add tests so that we can avoid breaking it in the future.

Speaking of tests, we use Appraisal to test against both HAML 4 and 5. We use rspec to write our tests. To run the test suite, execute the following from the root directory of the repository:

appraisal bundle install
appraisal bundle exec rspec

Community

All major discussion surrounding HAML-Lint happens on the GitHub issues page.

Changelog

If you're interested in seeing the changes and bug fixes between each version of haml-lint, read the HAML-Lint Changelog.

Author: sds
Source Code: https://github.com/sds/haml-lint
License: MIT license

#haml #lint