afilmory/plugins/eslint/eslint-check-i18n-json.js

// @ts-check
/** @type {import("eslint").ESLint.Plugin} */
import fs from 'node:fs'
import path from 'node:path'

import { cleanJsonText } from './utils.js'

export default {
  rules: {
    'valid-i18n-keys': {
      meta: {
        type: 'problem',
        docs: {
          description:
            'Ensure i18n JSON keys are flat and valid as object paths',
          category: 'Possible Errors',
          recommended: true,
        },
        fixable: null,
      },
      create(context) {
        return {
          Program(node) {
            const { filename, sourceCode } = context

            if (!filename.endsWith('.json')) return

            let json
            try {
              json = JSON.parse(cleanJsonText(sourceCode.text))
            } catch {
              context.report({
                node,
                message: 'Invalid JSON format',
              })
              return
            }

            const keys = Object.keys(json)
            const keyPrefixes = new Set()

            for (const key of keys) {
              if (key.includes('.')) {
                const parts = key.split('.')
                for (let i = 1; i < parts.length; i++) {
                  const prefix = parts.slice(0, i).join('.')
                  if (keys.includes(prefix)) {
                    context.report({
                      node,
                      message: `Invalid key structure: '${key}' conflicts with '${prefix}'`,
                    })
                  }
                  keyPrefixes.add(prefix)
                }
              }
            }

            for (const key of keys) {
              if (keyPrefixes.has(key)) {
                context.report({
                  node,
                  message: `Invalid key structure: '${key}' is a prefix of another key`,
                })
              }
            }
          },
        }
      },
    },
    'no-extra-keys': {
      meta: {
        type: 'problem',
        docs: {
          description:
            "Ensure non-English JSON files don't have extra keys not present in en.json",
          category: 'Possible Errors',
          recommended: true,
        },
        fixable: 'code', // Set fixable to "code"
      },
      create(context) {
        return {
          Program(node) {
            const { filename, sourceCode } = context

            if (!filename.endsWith('.json')) return

            const parts = filename.split(path.sep)
            const lang = parts.at(-1).split('.')[0]
            const namespace = parts.at(-2)

            if (lang === 'en') return

            let currentJson = {}
            let englishJson = {}

            try {
              currentJson = JSON.parse(sourceCode.text)
              const englishFilePath = path.join(
                path.dirname(filename),
                '../',
                namespace,
                'en.json',
              )
              englishJson = JSON.parse(fs.readFileSync(englishFilePath, 'utf8'))
            } catch (error) {
              context.report({
                node,
                message: `Error parsing JSON: ${error.message}`,
              })
              return
            }

            const extraKeys = Object.keys(currentJson).filter(
              (key) => !Object.prototype.hasOwnProperty.call(englishJson, key),
            )

            for (const key of extraKeys) {
              context.report({
                node,
                message: `Key "${key}" is present in ${lang}.json but not in en.json for namespace "${namespace}"`,
                fix(fixer) {
                  const newJson = Object.fromEntries(
                    Object.entries(currentJson).filter(
                      ([k]) => !extraKeys.includes(k),
                    ),
                  )

                  const newText = `${JSON.stringify(newJson, null, 2)}\n`

                  return fixer.replaceText(node, newText)
                },
              })
            }
          },
        }
      },
    },
  },
}