How to Use the JavaScript Standard Style Tool (with Examples)

JavaScript Standard Style is a widely used tool to lint and fix JavaScript code. It enforces a consistent coding style without any configuration and provides a straightforward command-line interface for developers to ensure their code adheres to a standard style. Being unopinionated and coming with zero configurations, it enhances productivity and maintainsability of codebases.

Use Case 1: Lint All JavaScript Source Files in the Current Directory

Code:

standard

Motivation:

Running standard without any additional arguments is the simplest way to ensure that all JavaScript files in the current directory follow the Standard JavaScript Style guidelines. This command scans the entire directory and flags any inconsistencies, promoting code uniformity right from the start. It’s particularly useful in projects where multiple developers work together, helping to prevent style-related conflicts before they arise.

Explanation:

• Simply using the command standard triggers the linter to review all .js files in the working directory for stylistic issues.
• The tool will showcase any violations of the Standard JavaScript Style, allowing developers to make informed decisions on whether to edit their code according to these guidelines.

Example output:

standard: Use JavaScript Standard Style (https://standardjs.com)
  /path/to/project/file1.js:10:5: 'console' is not defined.
  /path/to/project/file2.js:25:10: Missing semicolon.

Use Case 2: Lint Specific JavaScript File(s)

Code:

standard path/to/file1 path/to/file2 ...

Motivation:

This use case is perfect when you want to focus linting efforts on specific files rather than an entire directory. It’s efficient in scenarios where you are only making changes to part of the project and want to ensure those changes conform to the style rules before committing. This targeted approach saves time and system resources, focusing only on files of current interest.

Explanation:

• Adding path/to/file as an argument specifies which file(s) you want to lint, rather than performing a blanket check on all files.
• This is particularly useful in large projects where linting every file every time could be resource-intensive and unnecessary.

Example output:

standard: Use JavaScript Standard Style (https://standardjs.com)
  path/to/file1.js:12:18: Unexpected console statement.
  path/to/file2.js:37:5: 'myVar' is defined but never used.

Use Case 3: Apply Automatic Fixes During Linting

Code:

standard --fix

Motivation:

The --fix option is a convenient way to address and automatically correct certain types of stylistic problems identified by the tool. This is extremely useful during the development process, as it can save time that would otherwise be spent manually correcting repetitive style errors like spacing or line positions.

Explanation:

• The --fix flag instructs the linter to attempt to automatically fix issues that it can resolve, such as incorrect formatting or missing punctuation.
• This option is invaluable for routine maintenance and quick fixes, allowing developers to focus on more complex issues.

Example output:

standard: Use JavaScript Standard Style (https://standardjs.com)
  Fixed 10 problems in 2 files.

Use Case 4: Declare Any Available Global Variables

Code:

standard --global variable

Motivation:

Declaring globals using the --global flag is beneficial when your JavaScript code relies on variables defined in external scripts or libraries that are not initially present. This use case is crucial to prevent linting errors when custom globals are used and not recognized by the standard style linter.

Explanation:

• The --global argument allows for the declaration of global variables that you expect to be available in your environment but not defined in the source files.
• This helps to avoid false positives when the linter checks your code, preventing unnecessary distractions during development.

Example output:

standard: Use JavaScript Standard Style (https://standardjs.com)
  Declared global variable 'myGlobalVar'.

Use Case 5: Use a Custom ESLint Plugin When Linting

Code:

standard --plugin plugin

Motivation:

The ability to use custom ESLint plugins extends the functionality of Standard JavaScript Style, allowing developers to add specific linting rules or environments tailored to the needs of their projects. This makes the linter considerably more flexible and adaptable to unique project requirements.

Explanation:

• The --plugin flag allows for the integration of additional rules via ESLint plugins.
• Custom plugins provide the ability to target unique style and coding guidelines that may be project-specific or industry-standard beyond what comes out of the box.

Example output:

standard: Use JavaScript Standard Style (https://standardjs.com)
  Using additional ESLint plugin 'eslint-plugin-example'.

Use Case 6: Use a Custom JS Parser When Linting

Code:

standard --parser parser

Motivation:

Some JavaScript projects may use newer language features not yet fully supported by default parsers. In such cases, providing a custom JavaScript parser through the --parser option ensures the linter can accurately parse and validate the code without throwing errors due to syntax it doesn’t recognize.

Explanation:

• The --parser argument allows developers to specify a custom JavaScript parser.
• This ensures compatibility with language features used in the code, such as those found in TypeScript or JSX.

Example output:

standard: Use JavaScript Standard Style (https://standardjs.com)
  Using custom parser 'babel-eslint'.

Use Case 7: Use a Custom ESLint Environment When Linting

Code:

standard --env environment

Motivation:

Using a custom ESLint environment is essential when your codebase runs in specific execution environments, such as Node.js or browser contexts, that may have different global variables and modules. By putting JavaScript files in the right context, automatic checks can root out actual style discrepancies without marking valid usages as errors.

Explanation:

• The --env option specifies the environment in which the code is expected to run, telling the linter about the pre-defined global objects it should recognize.
• Environments are vital for adapting the linter’s understanding of what constitutes valid code for a specific execution domain like Node.js or web browsers.

Example output:

standard: Use JavaScript Standard Style (https://standardjs.com)
  Set environment to 'node'.

Conclusion:

Each one of these use cases demonstrates how incredibly versatile the JavaScript Standard Style tool can be when ensuring high-quality, styled, and error-free JavaScript code. Its ability to work with custom setups like plugins, parsers, and environments, along with the capability to fix certain issues automatically, empowers developers to confidently code knowing that their style remains consistent and maintainable.