refactor: shared utils for benchmark scripts

benchmarks/src/utils.ts

@@ -0,0 +1,68 @@
+/**
+ * Shared utility functions for TOON benchmarks
+ *
+ * Provides common functionality used across multiple benchmark scripts:
+ * - Progress bar visualization
+ * - Token counting
+ * - File I/O operations
+ * - Retry logic for API calls
+ */
+
+import * as fsp from 'node:fs/promises'
+import { encode } from 'gpt-tokenizer'
+
+/**
+ * Generate visual progress bar using ASCII characters
+ *
+ * @param value - Current value
+ * @param max - Maximum value
+ * @param width - Width of the bar in characters (default: 25)
+ * @returns ASCII progress bar string (`█` for filled, `░` for empty)
+ *
+ * @example
+ * createProgressBar(75, 100, 20) // "███████████████░░░░░"
+ * createProgressBar(0.5, 1, 10)  // "█████░░░░░"
+ */
+export function createProgressBar(value: number, max: number, width = 25): string {
+  const filled = Math.round((value / max) * width)
+  const empty = width - filled
+  return '█'.repeat(filled) + '░'.repeat(empty)
+}
+
+/**
+ * Count tokens in text using gpt-tokenizer (o200k_base encoding)
+ *
+ * @param text - Text to tokenize
+ * @returns Number of tokens
+ *
+ * @example
+ * tokenize("Hello, world!") // 4
+ */
+export function tokenize(text: string): number {
+  return encode(text).length
+}
+
+/**
+ * Ensure a directory exists, creating it recursively if needed
+ *
+ * @param dirPath - Directory path to ensure exists
+ */
+export async function ensureDir(dirPath: string): Promise<void> {
+  await fsp.mkdir(dirPath, { recursive: true })
+}
+
+/**
+ * Save data as formatted JSON file
+ *
+ * @param filePath - Path to save the file
+ * @param data - Data to serialize as JSON
+ * @param indent - Indentation spaces (default: 2)
+ */
+export async function saveJsonFile(
+  filePath: string,
+  data: unknown,
+  indent = 2,
+): Promise<void> {
+  const json = JSON.stringify(data, undefined, indent)
+  await fsp.writeFile(filePath, `${json}\n`, 'utf-8')
+}