facebookarchive/prepack

Implement Classes In The Interpreter

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#630 opened on May 10, 2017

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 (16 comments) (0 reactions) (0 assignees)JavaScript (14,268 stars) (520 forks)batch import
ES6help wantedinterpreter

Description

This would be a good start to being able to fully serialize classes. The serialization part is difficult because we have to serialize some features like methods with super calls using the class syntax.

However this issue is only about implementing the interpreter.

A good starting point is here:

https://github.com/facebook/prepack/blob/master/src/evaluators/ClassDeclaration.js

Then copying the spec piece by piece.

https://www.ecma-international.org/ecma-262/6.0/#sec-runtime-semantics-classdefinitionevaluation

The syntax is already in the Babel AST. Most of the Value model such as HomeObject and new.target is already in place.

Any previously unimplemented methods of the spec will need to be implemented. Such as MakeClassConstructor.

Running yarn test-test262 will run the full test suite which can be used to validate the final result.

yarn repl is good for experiments.

Contributor guide

Tech stack
javascript
Domain
backend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
JavaScript knowledgeECMAScript 6 class specPrepack evaluator architecture
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Start by examining the existing ClassDeclaration.js evaluator at https://github.com/facebook/prepack/blob/master/src/evaluators/ClassDeclaration.js. Then implement the ECMAScript 6 specification for class definition evaluation as per section 14.5.14. Use the test262 test suite (yarn test test262) to validate the implementation. The REPL (yarn repl) can be used for experiments.