mirror of
https://github.com/denoland/deno.git
synced 2024-12-29 10:39:10 -05:00
57 lines
2.2 KiB
Markdown
57 lines
2.2 KiB
Markdown
# serde_v8
|
|
|
|
Author: Aaron O'Mullan <aaron.omullan@gmail.com>
|
|
|
|
Serde support for encoding/decoding (rusty_)v8 values.
|
|
|
|
Broadly `serde_v8` aims to provide an expressive but ~maximally efficient
|
|
encoding layer to biject rust & v8/js values. It's a core component of deno's
|
|
op-layer and is used to encode/decode all non-buffer values.
|
|
|
|
**Original issue:**
|
|
[denoland/deno#9540](https://github.com/denoland/deno/issues/9540)
|
|
|
|
## Quickstart
|
|
|
|
`serde_v8` fits naturally into the serde ecosystem, so if you've already used
|
|
`serde` or `serde_json`, `serde_v8`'s API should be very familiar.
|
|
|
|
`serde_v8` exposes two key-functions:
|
|
|
|
- `to_v8`: maps `rust->v8`, similar to `serde_json::to_string`, ...
|
|
- `from_v8`: maps `v8->rust`, similar to `serde_json::from_str`, ...
|
|
|
|
## Best practices
|
|
|
|
Whilst `serde_v8` is compatible with `serde_json::Value` it's important to keep
|
|
in mind that `serde_json::Value` is essentially a loosely-typed value (think
|
|
nested HashMaps), so when writing ops we recommend directly using rust
|
|
structs/tuples or primitives, since mapping to `serde_json::Value` will add
|
|
extra overhead and result in slower ops.
|
|
|
|
I also recommend avoiding unecessary "wrappers", if your op takes a single-keyed
|
|
struct, consider unwrapping that as a plain value unless you plan to add fields
|
|
in the near-future.
|
|
|
|
Instead of returning "nothing" via `Ok(json!({}))`, change your return type to
|
|
rust's unit type `()` and returning `Ok(())`, `serde_v8` will efficiently encode
|
|
that as a JS `null`.
|
|
|
|
## Advanced features
|
|
|
|
If you need to mix rust & v8 values in structs/tuples, you can use the special
|
|
`serde_v8::Value` type, which will passthrough the original v8 value untouched
|
|
when encoding/decoding.
|
|
|
|
## TODO
|
|
|
|
- [ ] Experiment with KeyCache to optimize struct keys
|
|
- [ ] Experiment with external v8 strings
|
|
- [ ] Explore using
|
|
[json-stringifier.cc](https://chromium.googlesource.com/v8/v8/+/refs/heads/master/src/json/json-stringifier.cc)'s
|
|
fast-paths for arrays
|
|
- [ ] Improve tests to test parity with `serde_json` (should be mostly
|
|
interchangeable)
|
|
- [ ] Consider a `Payload` type that's deserializable by itself (holds scope &
|
|
value)
|
|
- [ ] Ensure we return errors instead of panicking on `.unwrap()`s
|