feat(drivers): add React Native MMKV driver and docs - #824

🏁 Script executed:

#!/bin/bash
set -e
file='docs/2.drivers/react-native-mmkv.md'
sed -n '1,90p' "$file"
printf '\n--- relevant repository references ---\n'
rg -n -C 3 'encryptionKey|AES-128|react-native-nitro-modules|react-native-mmkv' "$file" docs package.json 2>/dev/null || true

Repository: unjs/unstorage

Length of output: 9984

🌐 Web query:

react-native-mmkv v4 encryptionKey AES-128 16 bytes official documentation

💡 Result:

In react-native-mmkv v4, the encryption behavior regarding key length depends on the encryption type used [1][2]. For the default AES-128 encryption, the encryption key must be exactly 16 bytes long [3][1]. While some legacy documentation or general guidance may refer to a 16-byte maximum, the official requirement for AES-128 is a 16-byte key [3][1]. If you opt for AES-256 encryption, the key must be 32 bytes long [3][1]. Key technical details for v4: - Configuration: You provide the encryptionKey and optionally specify the encryptionType ('AES-128' or 'AES-256') when creating an MMKV instance [2][4]. - Enforcement: These length requirements are enforced at the native C++ layer; providing a key of an incorrect length will throw a runtime error [5][1][6]. - Best Practice: Encryption keys should be stored securely using platform-specific mechanisms like the iOS Keychain or Android Keystore, rather than being hardcoded in your JavaScript/TypeScript bundle [5][6]. - Runtime Changes: You can use the encrypt() method to enable encryption or re-encrypt an existing instance, and recrypt() (though marked as deprecated in some contexts in favor of encrypt/decrypt) to update the key [3][2]. Providing undefined to recrypt() or using decrypt() will remove encryption [3][7][4].

Citations:

• 1: https://github.com/margelo/react-native-skills/blob/HEAD/skills/react-native-mmkv/references/encryption.md
• 2: https://github.com/mrousavy/react-native-mmkv
• 3: https://cdn.jsdelivr.net/npm/react-native-mmkv@4.3.0/lib/specs/MMKV.nitro.d.ts
• 4: https://github.com/mrousavy/react-native-mmkv/blob/main/README.md
• 5: https://deepwiki.com/mrousavy/react-native-mmkv/4.3-configuration-options
• 6: https://deepwiki.com/mrousavy/react-native-mmkv/7.1-encryption-and-security
• 7: https://deepwiki.com/mrousavy/react-native-mmkv/4.1-core-api

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

🏁 Script executed:

#!/bin/bash
set -eu
printf '%s\n' '--- target document ---'
sed -n '1,110p' docs/2.drivers/react-native-mmkv.md
printf '%s\n' '--- references to Nitro installation and MMKV v4 ---'
rg -n -C 3 'react-native-nitro-modules|react-native-mmkv|encryptionKey|AES-128|v4' docs package.json package-lock.json yarn.lock pnpm-lock.yaml 2>/dev/null || true

Repository: unjs/unstorage

Length of output: 19765

🌐 Web query:

official react-native-mmkv v4 installation react-native-nitro-modules peer dependency

💡 Result:

In react-native-mmkv v4, react-native-nitro-modules is a required peer dependency [1][2][3]. This is because v4 has been entirely rewritten as a Nitro Module to utilize the Nitro framework for bridging JavaScript and native code [4][2][3]. Installation Requirements and Commands For a standard React Native project, you must install both packages [5][6]: npm install react-native-mmkv react-native-nitro-modules cd ios && pod install For Expo projects, use the following commands [5][6]: npx expo install react-native-mmkv react-native-nitro-modules npx expo prebuild Key Compatibility Notes 1. React Native Version: v4 requires React Native 0.76 or higher [5][6]. (Note: While some earlier v4 documentation mentioned 0.75.0, the current requirement is 0.76+ [5][6]). 2. Nitro Versioning: Specific versions of react-native-mmkv may require a minimum version of react-native-nitro-modules [7]. Always check the library's release notes if you encounter initialization crashes, as pinning to a specific compatible version of nitro-modules may be necessary if a newer release introduces regressions [7][8]. 3. Native Setup: On iOS, ensure your Podfile supports the native requirements (often handled automatically by autolinking) [2][3]. If you encounter build errors regarding static libraries, ensure you are using an updated version of MMKVCore (included by default in v4) or use:modular_headers => true in your Podfile [4]. You can verify the latest peer dependency requirements directly in the react-native-mmkv package.json or the official GitHub documentation [5][9].

Citations:

• 1: https://www.netguru.com/blog/mmkv-react-native-storage
• 2: https://deepwiki.com/mrousavy/react-native-mmkv/8-v4-migration-guide
• 3: https://deepwiki.com/mrousavy/react-native-mmkv/2-getting-started
• 4: https://github.com/mrousavy/react-native-mmkv/blob/main/docs/V4_UPGRADE_GUIDE.md
• 5: https://github.com/mrousavy/react-native-mmkv/
• 6: https://github.com/mrousavy/react-native-mmkv/blob/main/README.md
• 7: https://github.com/mrousavy/react-native-mmkv/releases/tag/v4.2.0
• 8: GitHub issue 980 in mrousavy/react-native-mmkv (link omitted to avoid creating a cross-reference)
• 9: https://www.npmjs.com/package/react-native-mmkv

🏁 Script executed:

#!/bin/bash
set -eu
python3 - <<'PY'
import urllib.request
urls = [
    "https://raw.githubusercontent.com/mrousavy/react-native-mmkv/main/docs/V4_UPGRADE_GUIDE.md",
    "https://raw.githubusercontent.com/mrousavy/react-native-mmkv/main/README.md",
]
for url in urls:
    print(f"--- {url} ---")
    try:
        text = urllib.request.urlopen(url, timeout=10).read().decode()
    except Exception as e:
        print(type(e).__name__, e)
        continue
    for i, line in enumerate(text.splitlines(), 1):
        if any(term in line.lower() for term in ("nitro", "install", "peer depend", "encryptionkey")):
            lo, hi = max(1, i-2), min(len(text.splitlines()), i+3)
            lines = text.splitlines()
            print("\n".join(f"{n}: {lines[n-1]}" for n in range(lo, hi+1)))
            print()
PY

Repository: unjs/unstorage

Length of output: 623

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#!/bin/bash
set -eu
for url in \
  https://raw.githubusercontent.com/mrousavy/react-native-mmkv/main/docs/V4_UPGRADE_GUIDE.md \
  https://raw.githubusercontent.com/mrousavy/react-native-mmkv/main/README.md \
  https://raw.githubusercontent.com/mrousavy/react-native-mmkv/main/package.json
do
  echo "--- $url ---"
  curl -ksSfL "$url" | grep -in -E -C 3 'nitro|install|peerDependencies|encryptionKey' | head -160 || true
done

Repository: unjs/unstorage

Length of output: 6554

🏁 Script executed:

#!/bin/bash
set -eu
curl -ksSfL https://raw.githubusercontent.com/mrousavy/react-native-mmkv/main/docs/V4_UPGRADE_GUIDE.md \
  | sed -n '1,180p'

Repository: unjs/unstorage

Length of output: 3314

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#!/bin/bash
set -euo pipefail

# Confirm all repository metadata uses a minimum version that supports the
# configuration fields declared in src/react-native-mmkv.d.ts.
rg -n -C 3 'react-native-mmkv|encryptionType|compareBeforeSet|recoveryStrategy' .

# Confirm the v4.0.0 upstream Configuration shape lacks the newer fields.
curl -fsSL \
  https://raw.githubusercontent.com/margelo/react-native-mmkv/v4.0.0/packages/react-native-mmkv/src/specs/MMKVFactory.nitro.ts \
  | sed -n '10,70p'

Repository: unjs/unstorage

Length of output: 15581

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#!/bin/bash
set -euo pipefail

for version in v4.0.0 v4.3.2; do
  echo "=== ${version} Configuration ==="
  curl -fsSL \
    "https://raw.githubusercontent.com/margelo/react-native-mmkv/${version}/packages/react-native-mmkv/src/specs/MMKVFactory.nitro.ts" \
    | rg -n -C 2 'interface Configuration|encryptionType|compareBeforeSet|recoveryStrategy|createMMKV'
done

Repository: unjs/unstorage

Length of output: 2856

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#!/bin/bash
set -euo pipefail

sed -n '220,248p' src/_drivers.ts
sed -n '28,50p' src/drivers/react-native-mmkv.ts

Repository: unjs/unstorage

Length of output: 1768

-  lib: { name: "react-native-mmkv", version: "^4.0.0" },
+  lib: { name: "react-native-mmkv", version: "^4.3.2" },

Apply this change in src/drivers/react-native-mmkv.ts and both MMKV entries in src/_drivers.ts.