✨ add helper function to generate random identifier

Foreign key constraints name will include 10 character long random identifier if not specified.
ref: https://api.rubyonrails.org/v4.2.0/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-add_foreign_key

The original implementation returns 10 character long random HEX string (e.g. "c5b6f2d87a", "4e2f7ab9c1", ...)
ref: https://github.com/rails/rails/blob/77fe87cccd90859e67c958cbf63d7e5662174fd8/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb#L984-L988

Author: tnyo43

frontend/packages/db-structure/src/parser/schemarb/generateRandomIdentifier.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from 'vitest'
+import { generateRandomIdentifier } from './generateRandomIdentifier.js'
+
+describe('generateRandomIdentifier', () => {
+  it('should generate random identifier with given length', () => {
+    expect(generateRandomIdentifier(4)).toHaveLength(4)
+    expect(generateRandomIdentifier(10)).toHaveLength(10)
+  })
+
+  it('should only contain alphanumeric characters', () => {
+    expect(/^[a-f0-9]+$/.test(generateRandomIdentifier(100))).toBe(true)
+  })
+
+  it('should return different values on multiple calls', () => {
+    // A collision is possible, though the probability is extremely low (16^{-10}, roughly 1 in 1,000,000,000)
+    const result1 = generateRandomIdentifier(10)
+    const result2 = generateRandomIdentifier(10)
+    expect(result1).not.toBe(result2)
+  })
+})

frontend/packages/db-structure/src/parser/schemarb/generateRandomIdentifier.ts

@@ -0,0 +1,4 @@
+export const generateRandomIdentifier = (length: number) =>
+  Array.from({ length }, () =>
+    '0123456789abcdef'.charAt(Math.floor(Math.random() * 16)),
+  ).join('')