https://github.com/denoland/eszip

A compact file format to losslessly serialize an ECMAScript module graph into a single file
https://github.com/denoland/eszip

deno esm javascript rust typescript

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A compact file format to losslessly serialize an ECMAScript module graph into a single file

• Host: GitHub
• URL: https://github.com/denoland/eszip
• Owner: denoland
• License: mit
• Created: 2021-02-14T22:40:09.000Z (almost 4 years ago)
• Default Branch: main
• Last Pushed: 2024-12-17T02:50:02.000Z (about 1 month ago)
• Last Synced: 2025-01-10T09:05:06.650Z (12 days ago)
• Topics: deno, esm, javascript, rust, typescript
• Language: Rust
• Homepage: https://crates.io/crates/eszip
• Size: 70.8 MB
• Stars: 235
• Watchers: 17
• Forks: 27
• Open Issues: 11
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# eszip

The eszip format lets you losslessly serialize an ECMAScript module graph

(represented by [`deno_graph::ModuleGraph`][module_graph]) into a single compact

file.

The eszip file format is designed to be compact and streaming capable. This

allows for efficient loading of large ECMAScript module graphs.

https://eszip-viewer.deno.dev/ is a tool for inspecting eszip files.

[module_graph]: https://docs.rs/deno_graph/latest/deno_graph/struct.ModuleGraph.html

## Examples

### Creating an eszip

```shell

cargo run --example eszip_builder https://deno.land/std/http/file_server.ts file_server.eszip2

```

### Viewing the contents of an eszip

```shell

cargo run --example eszip_viewer file_server.eszip2

```

### Loading the eszip into V8

```shell

cargo run --example eszip_load file_server.eszip2 https://deno.land/std/http/file_server.ts

```

## File format

The file format looks as follows:

```

Eszip:

| Magic (8) | Header size (4) | Header (n) | Header hash (32) | Sources size (4) | Sources (n) | SourceMaps size (4) | SourceMaps (n) |

Header:

( | Specifier size (4) | Specifier (n) | Entry type (1) | Entry (n) | )*

Entry (redirect):

| Specifier size (4) | Specifier (n) |

Entry (module):

| Source offset (4) | Source size (4) | SourceMap offset (4) | SourceMap size (4) | Module type (1) |

Sources:

( | Source (n) | Hash (32) | )*

SourceMaps:

( | SourceMap (n) | Hash (32) | )*

```

There is one optimization for empty source / source map entries. If both the

offset and size are set to 0, no entry and no hash is present in the data

sections for that module.

## Development

When opening a PR make sure to rebuild Wasm by running:

```

deno task build

```