Crate sledgehammer_bindgen

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sledgehammer bindgen

Sledgehammer bindgen provides faster rust batched bindings into javascript code.

wasm-bindgen is a lot more general it allows returning values and passing around a lot more different types of values. For most users wasm-bindgen is a beter choice. Sledgehammer bindgen is specifically that want low-level, fast access to javascript.
You can use sledgehammer bindgen with wasm-bindgen. See the docs and examples for more information.

Decoding strings are expensive to decode, but the cost doesn’t change much with the size of the string. Wasm-bindgen calls TextDecoder.decode for every string. Sledgehammer only calls TextEncoder.decode once per batch.
If the string is small, it is faster to decode the string in javascript to avoid the constant overhead of TextDecoder.decode
See this benchmark: https://jsbench.me/4vl97c05lb/5

You can cache strings in javascript to avoid decoding the same string multiple times.
If the string is static the string will be hashed by pointer instead of by value which is significantly faster.

Every operation is encoded as a sequence of bytes packed into an array. Every operation takes 1 byte plus whatever data is required for it.
Each operation is encoded in a batch of four as a u32. Getting a number from an array buffer has a high constant cost, but getting a u32 instead of a u8 is not more expensive. Sledgehammer bindgen reads the u32 and then splits it into the 4 individual bytes. It will shuffle and pack the bytes into as few buckets as possible and try to inline reads into the javascript.
See this benchmark: https://jsbench.me/csl9lfauwi/2

bindgen
Generates bindings for batched calls to js functions. The generated code is a Buffer struct with methods for each function.