rubocop for code quality and formatting in Rails

🔗 Parent Note

My Rails note

n350071🇯🇵 ・ Sep 11 '19

#rails

🤔 What is rubocop?

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📚 rubocop document
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RuboCop is a Ruby static code analyzer (a.k.a. linter) and code formatter. Out of the box it will enforce many of the guidelines outlined in the community Ruby Style Guide.
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🤔 How to use?

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put the .rubocop.yml on app directory and run following command.
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bundle exec rubocop --config .rubocop.yml

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then, get the results like this.
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path/to/file.rb::11.1  C: Layout/TrailingWhitespace: Trailing whitespace detected.
273 files inspected, 1 offenses detected

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It means that rubocop detects White Space which should be removed at the end of the line at row11, 1char, and the violation is only 1 in 273 files.
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🤔 How to fix it?

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1. Google with the detected message

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When you google with Layout/TrailingWhitespace, you'll see following explanation, then fix it.
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# The line in this example contains spaces after the 0.
# bad
x = 0
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# The line in this example ends directly after the 0.
# good
x = 0

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2. Auto correct

use -a option.
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bundle exec rubocop -a

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You can find other options on the 📚 document.
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