An ESLint plugin that enforces snake_case naming convention for object keys passed to Logger methods.
npm install @mjfwebb/enforce-logger-snake-caseAn ESLint plugin that enforces snake_case naming convention for object keys passed to Logger methods, ensuring consistent and predictable logging throughout your codebase.
``bash`
npm install --save-dev @mjfwebb/enforce-logger-snake-case
Register the plugin in your ESLint configuration.
`js
import enforceLoggerSnakeCase from "@mjfwebb/enforce-logger-snake-case";
export default [
{
plugins: {
"enforce-logger-snake-case": enforceLoggerSnakeCase,
},
rules: {
// Enforce snake_case keys in Logger method calls
"enforce-logger-snake-case/enforce-logger-snake-case": "error",
},
},
];
`
`js`
module.exports = {
plugins: ["enforce-logger-snake-case"],
rules: {
"enforce-logger-snake-case/enforce-logger-snake-case": "error",
},
};
Enforces snake_case naming convention for object keys when passing objects to Logger methods.
This rule applies to the following Logger methods:
- Logger.trace()
-
-
-
-
#### ❌ Incorrect
`js
// camelCase and PascalCase keys
Logger.info({ userId: 123 });
Logger.debug({ requestCount: 5 });
Logger.error({ errorMessage: "failed", ErrorCode: 500 });
Logger.warn({ connectionTimeout: 30 });
Logger.trace({ APIResponseTime: 100 });
// Mixed naming conventions
Logger.info({
user_id: 1,
userName: "test", // camelCase not allowed
userEmail: "test@example.com", // camelCase not allowed
});
// Shorthand properties with camelCase variable names
const userId = 123;
Logger.info({ userId }); // will be converted to { user_id: userId }
// Quoted identifiers (even if already snake_case)
Logger.info({ "user_id": 123 }); // quotes should be removed for consistency
// Spread properties (cannot be validated)
Logger.info({ ...otherObject });
Logger.info({ user_id: 1, ...otherObject });
// Computed properties (cannot be validated)
const key = "user_id";
Logger.info({ [key]: 123 });
Logger.info({ [getUserIdKey()]: 123 });
`
#### ✅ Correct
`js
// Unquoted snake_case identifiers
Logger.info({ user_id: 123 });
Logger.debug({ request_count: 5 });
Logger.error({ error_message: "failed", error_code: 500 });
Logger.warn({ connection_timeout: 30 });
Logger.trace({ api_response_time: 100 });
// Single word keys are valid
Logger.info({ message: "test" });
Logger.debug({ status: "ok" });
// Multiple snake_case keys
Logger.info({
user_id: 1,
user_name: "test",
user_email: "test@example.com",
});
// Shorthand properties with snake_case variable names
const user_id = 123;
Logger.info({ user_id });
// String literals with special characters (allowed since they can't be identifiers)
Logger.info({ "user-id": 123 });
Logger.info({ "Content-Type": "application/json" });
// Other loggers are not affected
console.log({ userId: 123 });
someOtherLogger.info({ userId: 123 });
// Non-object arguments are allowed
Logger.info("simple message");
Logger.info(123);
Logger.info();
`
This rule includes an automatic fix that converts camelCase and PascalCase keys to snake_case:
`js
// Before (auto-fix)
Logger.info({ userId: 123, requestCount: 5 });
// After (auto-fix applied)
Logger.info({ user_id: 123, request_count: 5 });
`
Shorthand properties are expanded when needed:
`js
// Before (auto-fix)
const userId = 123;
Logger.info({ userId });
// After (auto-fix applied)
const userId = 123;
Logger.info({ user_id: userId });
`
Quoted identifiers are unquoted:
`js
// Before (auto-fix)
Logger.info({ "user_id": 123 });
Logger.info({ "userId": 456 });
// After (auto-fix applied)
Logger.info({ user_id: 123 });
Logger.info({ user_id: 456 });
`
Run ESLint with the --fix flag to automatically convert all keys to snake_case:
`bash`
eslint --fix .
This rule enforces several constraints for consistent logging:
1. snake_case required: All property names must use snake_case (lowercase with underscores)
2. No quoted identifiers: Property names that could be valid identifiers must not be quoted
3. No spread properties: Spread syntax (...object) is not allowed as properties cannot be validated[key]
4. No computed properties: Computed property names () are not allowed as they cannot be validated at lint time
- Only applies to objects passed directly as the first argument to Logger methods
- Does not affect other logging libraries or console methods
- Snake_case format: lowercase letters and numbers, with underscores separating words
- Single word keys (all lowercase) are valid
- Valid pattern: ^[a-z][a-z0-9](?:_[a-z0-9]+)$
- Auto-fix converts camelCase and PascalCase to snake_case (e.g., → user_id, APIResponseTime → api_response_time`)
- String literals with special characters (hyphens, spaces, etc.) are allowed since they require quotes
MIT