eslint disable next line

Daniel Parker

3 min read

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26-02-2025

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ESLint is a powerful tool for maintaining consistent code quality and catching potential errors in JavaScript projects. However, there are times when you might need to temporarily disable a specific rule. This is where the // eslint-disable-next-line comment comes in handy. This article will explore its use, best practices, and alternatives.

Understanding // eslint-disable-next-line

The comment // eslint-disable-next-line tells ESLint to ignore the rule violations on the very next line of code. This is incredibly useful for situations where you know a rule is being broken intentionally and fixing it isn't immediately feasible or desirable. Perhaps you're working with legacy code, dealing with a complex edge case, or experimenting with a new approach.

Example:

// eslint-disable-next-line no-console
console.log('This will not trigger a warning.'); 

In this example, the no-console rule (which discourages using console.log for logging) is disabled for the following line. The console.log statement will not produce an ESLint warning.

When to Use // eslint-disable-next-line

While convenient, // eslint-disable-next-line shouldn't be used liberally. It's best reserved for specific scenarios:

• Temporary Workarounds: When you're working on a fix for a complex issue, temporarily disabling the related rule can keep your linter from generating distracting warnings.
• Legacy Code Integration: When integrating old code that doesn't adhere to your current coding style, selectively disabling rules can be helpful during the refactoring process.
• Known Exceptions: Sometimes there are genuine exceptions to a rule. In these situations, disabling the rule directly for that line is preferable to completely removing the rule from the ESLint configuration.
• Experimental Code: If you're trying out a new approach that doesn't immediately conform to your team's standards, disabling rules on a temporary basis can make experimentation smoother.

Specifying Rules to Disable

You can specify which rule to disable. This provides clarity and improves maintainability.

Example:

// eslint-disable-next-line no-unused-vars, max-len
const unusedVariable = 'This variable is intentionally unused for demonstration.';

Here, both no-unused-vars (unused variable) and max-len (maximum line length) rules are disabled for the next line. This is especially helpful when working with multiple rules and is more precise than simply disabling everything.

Alternatives to // eslint-disable-next-line

Using // eslint-disable-next-line can sometimes lead to an accumulation of disabled rules. It's always preferable to address the underlying issue if possible. Here are some alternatives:

• Fix the Code: The ideal solution. Rewrite the code to comply with the rule.
• Configure ESLint: Modify your ESLint configuration file (.eslintrc.js or similar) to adjust the rules. This permanently alters how ESLint behaves. Use cautiously.
• // eslint-disable and // eslint-enable: Disable and re-enable rules for a block of code. Use this for larger code sections where multiple violations occur.

Example of block commenting:

/* eslint-disable no-console */
console.log('This will not trigger a warning.');
console.log('Neither will this.');
/* eslint-enable no-console */

Best Practices

• Be Specific: Always specify the rule(s) to disable whenever possible.
• Temporary Measure: Use // eslint-disable-next-line as a temporary workaround, aiming to remove it eventually.
• Comment Clearly: Add a comment explaining why the rule is disabled. This helps future developers understand the context.
• Review Regularly: Periodically review your code to remove unnecessary disables.

Conclusion

// eslint-disable-next-line is a valuable tool for managing ESLint warnings when necessary. However, remember that it's a temporary solution. Always strive to fix the underlying code issues whenever practical to maintain clean, consistent, and well-maintained code. Use this comment responsibly, and always strive for code that conforms to your project's linting rules.