feat: initial release of @mobiletic/anonymizer

Framework-agnostic PII anonymization extracted from Mobiletic's chatbot.
Pluggable LLM detection + configurable regex fallback, deterministic
coreference, and streaming-safe de-anonymization.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/anonymizer.test.ts

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+import { describe, it, expect, vi } from 'vitest';
+import { Anonymizer, presets, type LlmProvider } from '../src/index.js';
+
+/** An LLM provider that is configured but always fails → forces the regex fallback. */
+const failingLlm = (overrides: Partial<LlmProvider> = {}): LlmProvider => ({
+  isConfigured: () => true,
+  anonymize: vi.fn().mockRejectedValue(new Error('LLM_NOT_CONFIGURED')),
+  anonymizeBatch: vi.fn().mockRejectedValue(new Error('LLM_NOT_CONFIGURED')),
+  ...overrides,
+});
+
+describe('Anonymizer (Swiss preset)', () => {
+  const svc = new Anonymizer({ llm: failingLlm(), patterns: presets.swiss });
+
+  it('skips anonymization (no LLM call) when there is no PII', async () => {
+    const llm = failingLlm();
+    const s = new Anonymizer({ llm, patterns: presets.swiss });
+    const r = await s.anonymize('Explique la différence entre INNER JOIN et LEFT JOIN');
+    expect(r.mapping).toEqual({});
+    expect(r.anon).toContain('INNER JOIN');
+    expect(llm.anonymize).not.toHaveBeenCalled();
+  });
+
+  it('falls back to regex for structured PII (email/phone/AVS)', async () => {
+    const r = await svc.anonymize('Contact: jean@exemple.ch, +41 79 123 45 67, AVS 756.1234.5678.90');
+    expect(r.anon).not.toContain('jean@exemple.ch');
+    expect(r.anon).not.toContain('756.1234.5678.90');
+    expect(Object.values(r.mapping)).toContain('jean@exemple.ch');
+    expect(svc.deanonymize(r.anon, r.mapping)).toContain('jean@exemple.ch');
+  });
+
+  it('deanonymizes a placeholder split across stream tokens (critical)', () => {
+    const mapping = { '[PER_1.NOM:M]': 'Alain JACCARD' };
+    const d = svc.makeStreamDeanonymizer(mapping);
+    let out = '';
+    out += d.push('Bonjour [PER_');
+    out += d.push('1.NOM');
+    out += d.push(':M], ravi');
+    out += d.flush();
+    expect(out).toBe('Bonjour Alain JACCARD, ravi');
+    expect(out).not.toContain('[PER_');
+  });
+
+  it('streams plain text through unchanged', () => {
+    const d = svc.makeStreamDeanonymizer({});
+    expect(d.push('Un INNER JOIN ') + d.push('retourne...') + d.flush()).toBe('Un INNER JOIN retourne...');
+  });
+
+  describe('anonymizeChunks', () => {
+    it('PII-free chunks → no LLM call, returned as-is', async () => {
+      const llm = failingLlm();
+      const s = new Anonymizer({ llm, patterns: presets.swiss });
+      const r = await s.anonymizeChunks(['Un INNER JOIN combine deux tables.'], {});
+      expect(llm.anonymizeBatch).not.toHaveBeenCalled();
+      expect(r.anon[0]).toContain('INNER JOIN');
+      expect(r.mapping).toEqual({});
+    });
+
+    it('reuses the question placeholder for the same person (deterministic, no LLM)', async () => {
+      const llm = failingLlm();
+      const s = new Anonymizer({ llm, patterns: presets.swiss });
+      const seed = { '[PER_1.NOM:M]': 'Alain JACCARD' };
+      const r = await s.anonymizeChunks(['Le dossier de Alain JACCARD est complet.'], seed);
+      expect(llm.anonymizeBatch).not.toHaveBeenCalled();
+      expect(r.anon[0]).toContain('[PER_1.NOM:M]');
+      expect(r.anon[0]).not.toContain('Alain JACCARD');
+      expect(r.mapping).toEqual(seed);
+    });
+
+    it('renumbers a NEW person that collides with the question placeholder', async () => {
+      const anonymizeBatch = vi.fn().mockResolvedValue({
+        segments: ['[PER_1.NOM:M] a signé.'],
+        mapping: { '[PER_1.NOM:M]': 'Bob Martin' },
+      });
+      const s = new Anonymizer({ llm: failingLlm({ anonymizeBatch }), patterns: presets.swiss });
+      const seed = { '[PER_1.NOM:M]': 'Alain JACCARD' };
+      const r = await s.anonymizeChunks(['Bob Martin a signé.'], seed);
+      expect(anonymizeBatch).toHaveBeenCalledTimes(1);
+      expect(r.anon[0]).toContain('[PER_2.NOM:M]');
+      expect(r.mapping['[PER_1.NOM:M]']).toBe('Alain JACCARD');
+      expect(r.mapping['[PER_2.NOM:M]']).toBe('Bob Martin');
+    });
+
+    it('falls back to regex (structured ids) when the LLM is unavailable', async () => {
+      const s = new Anonymizer({ llm: failingLlm(), patterns: presets.swiss });
+      const r = await s.anonymizeChunks(['Contact : jean@exemple.ch'], {});
+      expect(r.anon[0]).not.toContain('jean@exemple.ch');
+      expect(Object.values(r.mapping)).toContain('jean@exemple.ch');
+    });
+  });
+
+  describe('regex-only mode (no LLM provider)', () => {
+    const s = new Anonymizer({ patterns: presets.swiss });
+
+    it('still anonymizes structured PII without any provider', async () => {
+      const r = await s.anonymize('Écris à jean@exemple.ch');
+      expect(r.anon).not.toContain('jean@exemple.ch');
+      expect(Object.values(r.mapping)).toContain('jean@exemple.ch');
+    });
+
+    it('leaves a bare proper name untouched (no LLM to catch it)', async () => {
+      const r = await s.anonymize('Alain Jaccard a réussi');
+      // The name-hint flags it, but with no LLM the regex fallback finds no structured id.
+      expect(r.anon).toContain('Alain Jaccard');
+      expect(r.mapping).toEqual({});
+    });
+  });
+
+  describe('configurable presets', () => {
+    it('generic preset anonymizes an IPv4 address', async () => {
+      const s = new Anonymizer({ patterns: presets.generic });
+      const r = await s.anonymize('Serveur 192.168.1.42 indisponible');
+      expect(r.anon).not.toContain('192.168.1.42');
+      expect(Object.values(r.mapping)).toContain('192.168.1.42');
+    });
+
+    it('accepts a fully custom pattern set', async () => {
+      const s = new Anonymizer({ patterns: [{ tag: 'TICKET', re: /\bJIRA-\d+\b/g }] });
+      const r = await s.anonymize('Voir JIRA-123');
+      expect(r.anon).toContain('[TICKET_1]');
+      expect(r.mapping['[TICKET_1]']).toBe('JIRA-123');
+    });
+  });
+});