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Version: v0.0.4

Quickstart

Generate reproducible, synthetic-by-construction fixtures in a few lines. A seed determines the output entirely, so a fixture set regenerates identically anywhere.

Draw a synthetic value​

The safe providers each draw from a reserved, never-collide source. Everything is a pure function of an explicit seeded generator (createRng):

import { createRng, safe, isSyntheticSsn } from "@cosyte/synth";

const rng = createRng(42);
const nationalId = safe.ssn(rng);

// The SSN is always drawn from the SSA never-issued space - it cannot be a real SSN.
isSyntheticSsn(nationalId); // => true

Generate an HL7 v2 message​

The @cosyte/synth/hl7 subpath builds messages through @cosyte/hl7, so they are spec-clean by construction and round-trip with zero warnings:

import { generateAdt, roundTrip } from "@cosyte/synth/hl7";

const result = roundTrip(generateAdt({ seed: 7, trigger: "A08" }));

result.warnings; // => []

Build a reproducible corpus​

hl7Corpus returns a deep-frozen, self-describing Corpus - a seed plus a manifest of what was generated. Pin the seed and every downstream test gets a stable fixture set:

import { hl7Corpus } from "@cosyte/synth/hl7";

const corpus = hl7Corpus({ seed: 2026, count: 3 });

corpus.artifacts.length; // => 3

Determinism is the contract​

The same seed yields byte-identical output - this is a tested invariant, not a nicety:

import { generateAdt } from "@cosyte/synth/hl7";

const a = generateAdt({ seed: 99 }).toString();
const b = generateAdt({ seed: 99 }).toString();

a === b; // => true

Next​

  • Core Concepts - synthetic-by-construction, determinism, the round-trip gate.
  • API Reference - every export, generated from source.