Initial commit: Text encoding component with UTF-8 polyfills

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

interfaces.ts

@@ -0,0 +1,158 @@
+/**
+ * Text Encoding Interface Definitions
+ *
+ * Provides UTF-8 text encoding/decoding capabilities for React Native
+ * Compatible with the standard TextEncoder/TextDecoder Web API
+ *
+ * @module text-encoding@1.0.0/interfaces
+ */
+
+/**
+ * TextEncoder interface - encodes strings to UTF-8 byte arrays
+ */
+export interface ITextEncoder {
+  /**
+   * The encoding format (always 'utf-8' for this implementation)
+   */
+  readonly encoding: string;
+
+  /**
+   * Encode a string into a Uint8Array using UTF-8 encoding
+   * @param input The string to encode
+   * @returns UTF-8 encoded byte array
+   */
+  encode(input?: string): Uint8Array;
+
+  /**
+   * Encode a string into an existing Uint8Array (partial encoding)
+   * @param source The string to encode
+   * @param destination The array to write to
+   * @returns Object with read (chars) and written (bytes) counts
+   */
+  encodeInto?(source: string, destination: Uint8Array): TextEncoderEncodeIntoResult;
+}
+
+/**
+ * TextDecoder interface - decodes UTF-8 byte arrays to strings
+ */
+export interface ITextDecoder {
+  /**
+   * The encoding format (always 'utf-8' for this implementation)
+   */
+  readonly encoding: string;
+
+  /**
+   * Whether to throw on invalid sequences (vs replacement char)
+   */
+  readonly fatal: boolean;
+
+  /**
+   * Whether to ignore BOM (byte order mark)
+   */
+  readonly ignoreBOM: boolean;
+
+  /**
+   * Decode a byte array into a string using UTF-8 decoding
+   * @param input The bytes to decode (Uint8Array or ArrayBuffer)
+   * @param options Decoding options
+   * @returns Decoded string
+   */
+  decode(input?: ArrayBufferView | ArrayBuffer, options?: TextDecodeOptions): string;
+}
+
+/**
+ * Result of encodeInto operation
+ */
+export interface TextEncoderEncodeIntoResult {
+  /**
+   * Number of UTF-16 code units read from source
+   */
+  read: number;
+
+  /**
+   * Number of bytes written to destination
+   */
+  written: number;
+}
+
+/**
+ * Options for text decoding
+ */
+export interface TextDecodeOptions {
+  /**
+   * Whether this is a streaming decode (more data coming)
+   */
+  stream?: boolean;
+}
+
+/**
+ * Options for TextDecoder constructor
+ */
+export interface TextDecoderOptions {
+  /**
+   * If true, throw on invalid byte sequences
+   */
+  fatal?: boolean;
+
+  /**
+   * If true, ignore byte order mark
+   */
+  ignoreBOM?: boolean;
+}
+
+/**
+ * Factory for creating encoder/decoder instances
+ */
+export interface ITextEncodingFactory {
+  /**
+   * Create a new TextEncoder instance
+   */
+  createEncoder(): ITextEncoder;
+
+  /**
+   * Create a new TextDecoder instance
+   * @param label Encoding label (default 'utf-8')
+   * @param options Decoder options
+   */
+  createDecoder(label?: string, options?: TextDecoderOptions): ITextDecoder;
+
+  /**
+   * Check if TextEncoder/TextDecoder are natively available
+   */
+  isNativelySupported(): boolean;
+}
+
+/**
+ * Text encoding service for shared instances
+ */
+export interface ITextEncodingService {
+  /**
+   * Shared encoder instance
+   */
+  readonly encoder: ITextEncoder;
+
+  /**
+   * Shared decoder instance
+   */
+  readonly decoder: ITextDecoder;
+
+  /**
+   * Encode string to bytes
+   */
+  encode(text: string): Uint8Array;
+
+  /**
+   * Decode bytes to string
+   */
+  decode(bytes: Uint8Array | ArrayBuffer | number[]): string;
+
+  /**
+   * Convert string to UTF-8 byte array (convenience method)
+   */
+  stringToUtf8(text: string): Uint8Array;
+
+  /**
+   * Convert UTF-8 byte array to string (convenience method)
+   */
+  utf8ToString(bytes: Uint8Array | number[]): string;
+}