Skip to content
Generates wasm sourcemaps from dwarf debug information
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.
dub.sdl fix license Nov 5, 2019

Wasm Sourcemaps

Standalone utility to generate sourcemaps from WebAssembly files.

How to install

First install a D compiler. curl | bash -s or follow the instructions at

Then you can run this tools with dub run wasm-sourcemaps -- --help.


Make sure your WebAssembly file contains dwarf debug information.

Usage: wasm-sourcemaps [--help] [--output=<string>] [--embed=<bool>]
                       [--embed-base-url=<string>] [--include-sources=<bool>] file

Positional arguments:
 file            Input file

Optional arguments:
 --help, -h      Prints this help.
 --output <string>
                 Output file, default is same as input with '.map' extension
                 added, use '-' for stdout
 --embed <bool>  embeds the sourcemap url in wasm file. Default is true. This adds a
                 sourceMappingURL custom section in the wasm file with a
                 reference to the sourcemap file. This allows browsers to
                 automatically load the sourcemap file.
 --embed-base-url <string>
                 sets the url used when embedding the sourcemap url in the
                 webassembly file. Default is './'.
 --include-sources <bool>
                 includes the source files in the sourcemap. Default is

How it works

It extracts dwarf debug information from the WebAssembly file and converts it to a sourcemap version 3.


D mixins aren't included in the sourcemap.

Sourcemaps themselves contain no type information so a debugger (e.g. browser devtools) will only show raw WebAssembly types (i32u, i32s, f32, f64).


Part of the dwarf code was taken from the elf-d project by Yazan Dabain. That code, as well as this project, is licensed under the Boost Software License, Version 1.0.

You can’t perform that action at this time.