> ## Documentation Index
> Fetch the complete documentation index at: https://docs.solved.gg/llms.txt
> Use this file to discover all available pages before exploring further.

# I1 — ES Engine

> Initiative I1: make scripty's Zig VM fully compatible with the latest ECMAScript edition (ES2026 baseline).

# I1 — ES Engine

**Goal:** ship a Zig-native JavaScript engine that is **fully compatible** with the **latest ECMAScript** edition.

| Field             | Value                                                                    |
| ----------------- | ------------------------------------------------------------------------ |
| **Initiative**    | I1                                                                       |
| **Edition pin**   | **ECMAScript 2026** ([ECMA-262](https://262.ecma-international.org/))    |
| **Oracle**        | [Test262](https://github.com/tc39/test262) language tests (in-scope set) |
| **Hard gate for** | Tag `0.0.1` language bar                                                 |
| **Engine**        | Own VM in Zig — never V8 / JSC / SpiderMonkey                            |

## Why this is first

Every other product surface — exclusive Bun/Deno APIs, Node-compat, frameworks, DX, desktop embed — assumes correct language semantics. Partial engines produce matrices that look green while real programs fail in surprising ways.

Pre-v0.0.1 therefore **gates the tag on language completeness**, not on framework dogfood.

## Success definition

You may claim ES edition compatibility for `0.0.1` only when **all** of the following hold:

1. [Feature matrix](/scripty/v0.0.1-dev/es/feature-matrix) in-scope rows are `supported` or `dogfooded`
2. [Test262](/scripty/v0.0.1-dev/es/test262) CI runs on Linux for the in-scope set with **zero open blockers**
3. Fail-closed behavior outside the matrix (no silent wrong success)
4. Edition pin and Test262 pin are recorded in [Sources](/scripty/v0.0.1-dev/reference/sources)

Exact in/out boundaries: [Scope](/scripty/v0.0.1-dev/es/scope).

## Current engine reality (honest)

scripty already has an early kernel: lexer/parser, bytecode interpreter, partial values, promises/microtasks, timers, local ESM, TS type strip, JSX transform. That is a starting point — **not** ES2026 completeness.

| Area                                            | Typical status today    |
| ----------------------------------------------- | ----------------------- |
| Parse / interpret smokes                        | `partial`               |
| Promises / timers                               | `supported` (smokes)    |
| Symbols, BigInt, Proxy, full RegExp, TypedArray | mostly `unsupported`    |
| Test262 harness                                 | not yet the product bar |
| Built-in breadth                                | sparse                  |

## Work packages

| Doc                                                     | Contents                                 |
| ------------------------------------------------------- | ---------------------------------------- |
| [Scope](/scripty/v0.0.1-dev/es/scope)                   | In/out, Annex B, host-defined exclusions |
| [Phases](/scripty/v0.0.1-dev/es/phases)                 | ES-0 … ES-9 build sequence               |
| [Feature matrix](/scripty/v0.0.1-dev/es/feature-matrix) | Edition feature rows                     |
| [Built-ins](/scripty/v0.0.1-dev/es/builtins)            | Built-in object inventory                |
| [Module system](/scripty/v0.0.1-dev/es/module-system)   | Language-level ESM (not Node resolve)    |
| [Test262](/scripty/v0.0.1-dev/es/test262)               | Harness, CI, triage                      |

## Risks

| Risk                                     | Note                                          |
| ---------------------------------------- | --------------------------------------------- |
| Multi-year surface                       | Phases ES-0…ES-9 keep progress shippable      |
| Spec / Test262 churn                     | Re-pin process required                       |
| Premature exclusive APIs                 | Prefer after ES-5 for real modules + builtins |
| Confusing “ES complete” with “npm works” | Explicitly out of scope for I1                |

## Next

1. Read [Scope](/scripty/v0.0.1-dev/es/scope)
2. Track [Phases](/scripty/v0.0.1-dev/es/phases)
3. Update [Feature matrix](/scripty/v0.0.1-dev/es/feature-matrix) as work lands


## Related topics

- [I1 — ES Engine](/scripty/v0.0.1-dev/es/index.md)
- [Initiatives](/scripty/v0.0.1-dev/initiatives.md)
- [Roadmap](/scripty/v0.0.1-dev/roadmap.md)
- [ES scope](/scripty/v0.0.1-dev/es/scope.md)
- [ES phases](/scripty/v0.0.1-dev/es/phases.md)