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@webassemblyjs/wasm-edit

> Rewrite a WASM binary

Replace in-place an AST node in the binary.

# Installation

yarn add @webassemblyjs/wasm-edit

# Usage

Update:

import { edit } from "@webassemblyjs/wasm-edit";
const binary = [/*...*/];
const visitors = {
ModuleImport({ node }) {
node.module = "foo";
node.name = "bar";
}
};
const newBinary = edit(binary, visitors);

Replace:

import { edit } from "@webassemblyjs/wasm-edit";
const binary = [/*...*/];
const visitors = {
Instr(path) {
const newNode = t.callInstruction(t.indexLiteral(0));
path.replaceWith(newNode);
}
};
const newBinary = edit(binary, visitors);

Remove:

import { edit } from "@webassemblyjs/wasm-edit";
const binary = [/*...*/];
const visitors = {
ModuleExport({ node }) {
path.remove()
}
};
const newBinary = edit(binary, visitors);

Insert:

import { add } from "@webassemblyjs/wasm-edit";
const binary = [/*...*/];
const newBinary = add(actualBinary, [
t.moduleImport("env", "mem", t.memory(t.limit(1)))
]);

# Providing the AST

Providing an AST allows you to handle the decoding yourself, here is the API:

addWithAST(Program, ArrayBuffer, Array<Node>): ArrayBuffer;
editWithAST(Program, ArrayBuffer, visitors): ArrayBuffer;

Note that the AST will be updated in-place.