@webassemblyjs/ast
Advanced tools
Package description
The @webassemblyjs/ast package is a toolchain for WebAssembly manipulation which allows you to parse, validate, and generate WebAssembly code. It provides an Abstract Syntax Tree (AST) representation of WebAssembly modules, enabling programmatic analysis and transformation of Wasm code.
Parsing WebAssembly binary
This feature allows you to parse a WebAssembly binary into an AST. The code sample demonstrates how to use the wasm-parser submodule to decode a binary representation of a WebAssembly module.
"use strict";\nconst { decode } = require('@webassemblyjs/wasm-parser');\nconst binary = new Uint8Array([0x00, 0x61, 0x73, 0x6d, ...]);\nconst ast = decode(binary);\nconsole.log(ast);Generating WebAssembly binary
This feature enables you to generate a WebAssembly binary from an AST. The code sample shows how to create an empty WebAssembly module using the ast submodule and then encode it into a binary with wasm-gen.
"use strict";\nconst { encode } = require('@webassemblyjs/wasm-gen');\nconst t = require('@webassemblyjs/ast');\nconst module = t.module([], []);\nconst binary = encode(module);\nconsole.log(new Uint8Array(binary));Traversing and modifying the AST
This feature is for traversing the AST and applying modifications. The code sample illustrates how to traverse an existing AST and log each ModuleImport node encountered.
"use strict";\nconst { traverse } = require('@webassemblyjs/ast');\nconst ast = ...; // Assume this is an existing AST\ntraverse(ast, {\n ModuleImport(path) {\n console.log(path.node);\n }\n});The wast-parser package is similar to @webassemblyjs/ast in that it can parse WebAssembly text format (WAT) into an AST. However, it focuses on the text format rather than the binary format and does not provide binary generation capabilities.
Binaryen is a compiler and toolchain infrastructure library for WebAssembly, written in C++. It has bindings for JavaScript and provides similar functionalities such as parsing, optimization, and generation of WebAssembly code. Compared to @webassemblyjs/ast, Binaryen offers a broader range of optimization tools and is implemented in a different programming language.
WABT (The WebAssembly Binary Toolkit) is a suite of tools for WebAssembly, including a decoder, an interpreter, and a binary format validator. It is similar to @webassemblyjs/ast in that it allows manipulation of WebAssembly binaries but is a standalone toolkit rather than an npm package.
Readme
AST utils for webassemblyjs
npm install @webassemblyjs/ast
import { traverse } from "@webassemblyjs/ast";
traverse(ast, {
Module(path) {
console.log(path.node);
}
});
import { signatures } from "@webassemblyjs/ast";
console.log(signatures);
signature(object, name)identifier(value)valtype(name)stringLiteral(value)program(body)module(id, fields)binaryModule(id, blob)quoteModule(id, string)moduleExport(name, type, id)func(name, params, result, body)objectInstruction(id, object, args, namedArgs)instruction(id, args, namedArgs)loopInstruction(label, resulttype, instr)blockInstruction(label, instr, result)numberLiteral(rawValue, instructionType)callInstruction(index, instrArgs)ifInstruction(testLabel, result, test, consequent, alternate)withLoc(n, end, start)moduleImport(module, name, descr)globalImportDescr(valtype, mutability)funcParam(valtype, id)funcImportDescr(id, params, results)table(elementType, limits, name, elements)limits(min, max)memory(limits, id)data(memoryIndex, offset, init)global(globalType, init, name)globalType(valtype, mutability)byteArray(values)leadingComment(value)blockComment(value)indexLiteral(value)memIndexLiteral(value)typeInstructionFunc(params, result, id)callIndirectInstruction(params, results, intrs)start(index)elem(table, offset, funcs)FAQs
AST utils for webassemblyjs
We found that @webassemblyjs/ast demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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