Duplicated Code

Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:

Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.

When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).

Tuning

This issue has a mass of 45.

We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.

The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.

If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.

See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.

Refactorings

• Extract Method
• Extract Class
• Form Template Method
• Introduce Null Object
• Pull Up Method
• Pull Up Field
• Substitute Algorithm

Further Reading

• Don't Repeat Yourself on the C2 Wiki
• Duplicated Code on SourceMaking
• Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76

Duplicated Code

Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:

Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.

When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).

Tuning

This issue has a mass of 45.

We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.

The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.

If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.

See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.

Refactorings

• Extract Method
• Extract Class
• Form Template Method
• Introduce Null Object
• Pull Up Method
• Pull Up Field
• Substitute Algorithm

Further Reading

• Don't Repeat Yourself on the C2 Wiki
• Duplicated Code on SourceMaking
• Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

Rule: jsdoc-format

Enforces basic format rules for JSDoc comments.

The following rules are enforced for JSDoc comments (comments starting with /**):

• each line contains an asterisk and asterisks must be aligned
• each asterisk must be followed by either a space or a newline (except for the first and the last)
• the only characters before the asterisk on each line must be whitespace characters
• one line comments must start with /** and end with */
• multiline comments don't allow text after /** in the first line (with option "check-multiline-start")

Rationale

Helps maintain a consistent, readable style for JSDoc comments.

Config

You can optionally specify the option "check-multiline-start" to enforce the first line of a multiline JSDoc comment to be empty.

Examples

"jsdoc-format": true

"jsdoc-format": true,check-multiline-start

Schema

{
  "type": "array",
  "minItems": 0,
  "maxItems": 1,
  "items": {
    "type": "string",
    "enum": [
      "check-multiline-start"
    ]
  }
}

For more information see this page.

Rule: max-classes-per-file

A file may not contain more than the specified number of classes

Rationale

Ensures that files have a single responsibility so that that classes each exist in their own files

Config

The one required argument is an integer indicating the maximum number of classes that can appear in a file. An optional argument "exclude-class-expressions" can be provided to exclude class expressions from the overall class count.

Examples

"max-classes-per-file": true,1

"max-classes-per-file": true,5,exclude-class-expressions

Schema

{
  "type": "array",
  "items": [
    {
      "type": "number",
      "minimum": 1
    },
    {
      "type": "string",
      "enum": [
        "exclude-class-expressions"
      ]
    }
  ],
  "additionalItems": false,
  "minLength": 1,
  "maxLength": 2
}

For more information see this page.

Rule: object-literal-shorthand

Enforces/disallows use of ES6 object literal shorthand.

Notes

• Has Fix

Config

"always" assumed to be default option, thus with no options provided the rule enforces object literal methods and properties shorthands. With "never" option provided, any shorthand object literal syntax causes an error.

The rule can be configured in a more granular way. With {"property": "never"} provided (which is equivalent to {"property": "never", "method": "always"}), the rule only flags property shorthand assignments, and respectively with {"method": "never"} (equivalent to {"property": "always", "method": "never"}), the rule fails only on method shorthands.

Examples

"object-literal-shorthand": true

"object-literal-shorthand": true,never

"object-literal-shorthand": true,[object Object]

Schema

{
  "oneOf": [
    {
      "type": "string",
      "enum": [
        "never"
      ]
    },
    {
      "type": "object",
      "properties": {
        "property": {
          "type": "string",
          "enum": [
            "never"
          ]
        },
        "method": {
          "type": "string",
          "enum": [
            "never"
          ]
        }
      },
      "minProperties": 1,
      "maxProperties": 2
    }
  ]
}

For more information see this page.

Rule: ban-types

Bans specific types from being used. Does not ban the corresponding runtime objects from being used.

Notes

• TypeScript Only

Config

A list of ["regex", "optional explanation here"], which bans types that match regex

Examples

"ban-types": true,Object,Use {} instead.,String

Schema

{
  "type": "list",
  "listType": {
    "type": "array",
    "items": {
      "type": "string"
    },
    "minLength": 1,
    "maxLength": 2
  }
}

For more information see this page.

Rule: object-literal-shorthand

Enforces/disallows use of ES6 object literal shorthand.

Notes

• Has Fix

Config

"always" assumed to be default option, thus with no options provided the rule enforces object literal methods and properties shorthands. With "never" option provided, any shorthand object literal syntax causes an error.

The rule can be configured in a more granular way. With {"property": "never"} provided (which is equivalent to {"property": "never", "method": "always"}), the rule only flags property shorthand assignments, and respectively with {"method": "never"} (equivalent to {"property": "always", "method": "never"}), the rule fails only on method shorthands.

Examples

"object-literal-shorthand": true

"object-literal-shorthand": true,never

"object-literal-shorthand": true,[object Object]

Schema

{
  "oneOf": [
    {
      "type": "string",
      "enum": [
        "never"
      ]
    },
    {
      "type": "object",
      "properties": {
        "property": {
          "type": "string",
          "enum": [
            "never"
          ]
        },
        "method": {
          "type": "string",
          "enum": [
            "never"
          ]
        }
      },
      "minProperties": 1,
      "maxProperties": 2
    }
  ]
}

For more information see this page.

Rule: jsdoc-format

Enforces basic format rules for JSDoc comments.

The following rules are enforced for JSDoc comments (comments starting with /**):

• each line contains an asterisk and asterisks must be aligned
• each asterisk must be followed by either a space or a newline (except for the first and the last)
• the only characters before the asterisk on each line must be whitespace characters
• one line comments must start with /** and end with */
• multiline comments don't allow text after /** in the first line (with option "check-multiline-start")

Rationale

Helps maintain a consistent, readable style for JSDoc comments.

Config

You can optionally specify the option "check-multiline-start" to enforce the first line of a multiline JSDoc comment to be empty.

Examples

"jsdoc-format": true

"jsdoc-format": true,check-multiline-start

Schema

{
  "type": "array",
  "minItems": 0,
  "maxItems": 1,
  "items": {
    "type": "string",
    "enum": [
      "check-multiline-start"
    ]
  }
}

For more information see this page.

Rule: jsdoc-format

Enforces basic format rules for JSDoc comments.

The following rules are enforced for JSDoc comments (comments starting with /**):

• each line contains an asterisk and asterisks must be aligned
• each asterisk must be followed by either a space or a newline (except for the first and the last)
• the only characters before the asterisk on each line must be whitespace characters
• one line comments must start with /** and end with */
• multiline comments don't allow text after /** in the first line (with option "check-multiline-start")

Rationale

Helps maintain a consistent, readable style for JSDoc comments.

Config

You can optionally specify the option "check-multiline-start" to enforce the first line of a multiline JSDoc comment to be empty.

Examples

"jsdoc-format": true

"jsdoc-format": true,check-multiline-start

Schema

{
  "type": "array",
  "minItems": 0,
  "maxItems": 1,
  "items": {
    "type": "string",
    "enum": [
      "check-multiline-start"
    ]
  }
}

For more information see this page.

Rule: jsdoc-format

Enforces basic format rules for JSDoc comments.

The following rules are enforced for JSDoc comments (comments starting with /**):

• each line contains an asterisk and asterisks must be aligned
• each asterisk must be followed by either a space or a newline (except for the first and the last)
• the only characters before the asterisk on each line must be whitespace characters
• one line comments must start with /** and end with */
• multiline comments don't allow text after /** in the first line (with option "check-multiline-start")

Rationale

Helps maintain a consistent, readable style for JSDoc comments.

Config

You can optionally specify the option "check-multiline-start" to enforce the first line of a multiline JSDoc comment to be empty.

Examples

"jsdoc-format": true

"jsdoc-format": true,check-multiline-start

Schema

{
  "type": "array",
  "minItems": 0,
  "maxItems": 1,
  "items": {
    "type": "string",
    "enum": [
      "check-multiline-start"
    ]
  }
}

For more information see this page.