workflow_wasm/extensions/
jsvalue.rs

1//! JsValue to native Rust datatypes conversion utilities.
2//! These utilities marshall incoming data for different types
3//! of representations and convert them to native Rust datatypes.
4//! For example, a `Vec<u8>` can be converted from a Uint8Array
5//! or from a hex-encoded string.
6
7use crate::error::Error;
8use js_sys::Uint8Array;
9use wasm_bindgen::prelude::*;
10
11/// Extension trait converting a [`JsValue`] into native Rust integer and byte types.
12pub trait JsValueExtension {
13    /// Convert the value to a `u8`, erroring if it is not a number or is out of range.
14    fn try_as_u8(&self) -> Result<u8, Error>;
15    /// Convert the value to a `u16`, erroring if it is not a number or is out of range.
16    fn try_as_u16(&self) -> Result<u16, Error>;
17    /// Convert the value to a `u32`, erroring if it is not a number or is out of range.
18    fn try_as_u32(&self) -> Result<u32, Error>;
19    /// Convert the value to a `u64`, accepting a hex string, a `BigInt`, or a number.
20    fn try_as_u64(&self) -> Result<u64, Error>;
21    /// Convert the value to a `Vec<u8>`, accepting a hex string or a byte array.
22    fn try_as_vec_u8(&self) -> Result<Vec<u8>, Error>;
23}
24
25impl JsValueExtension for JsValue {
26    fn try_as_u8(&self) -> Result<u8, Error> {
27        let f = self
28            .as_f64()
29            .ok_or_else(|| Error::WrongType(format!("value is not a number: `{self:?}`")))?;
30        if f < 0.0 || f > u8::MAX as f64 {
31            Err(Error::Bounds(format!(
32                "value `{f}` is out of bounds (0..{})",
33                u8::MAX
34            )))
35        } else {
36            Ok(f as u8)
37        }
38    }
39
40    fn try_as_u16(&self) -> Result<u16, Error> {
41        let f = self
42            .as_f64()
43            .ok_or_else(|| Error::WrongType(format!("value is not a number: `{self:?}`")))?;
44        if f < 0.0 || f > u16::MAX as f64 {
45            Err(Error::Bounds(format!(
46                "value `{f}` is ount of bounds (0..{})",
47                u16::MAX
48            )))
49        } else {
50            Ok(f as u16)
51        }
52    }
53
54    fn try_as_u32(&self) -> Result<u32, Error> {
55        let f = self
56            .as_f64()
57            .ok_or_else(|| Error::WrongType(format!("value is not a number: `{self:?}`")))?;
58        if f < 0.0 || f > u32::MAX as f64 {
59            Err(Error::Bounds(format!(
60                "value `{f}` is ount of bounds (0..{})",
61                u32::MAX
62            )))
63        } else {
64            Ok(f as u32)
65        }
66    }
67
68    fn try_as_u64(&self) -> Result<u64, Error> {
69        if self.is_string() {
70            let hex_str = self.as_string().unwrap();
71            if hex_str.len() > 16 {
72                Err(Error::WrongSize(
73                    "try_as_u64(): supplied string must be < 16 chars".to_string(),
74                ))
75            } else {
76                let mut out = [0u8; 8];
77                let mut input = [b'0'; 16];
78                let start = input.len() - hex_str.len();
79                input[start..].copy_from_slice(hex_str.as_bytes());
80                faster_hex::hex_decode(&input, &mut out)?;
81                Ok(u64::from_be_bytes(out))
82            }
83        } else if self.is_bigint() {
84            Ok(self.clone().try_into().map_err(|err| {
85                Error::Convert(format!(
86                    "try_as_u64(): unable to convert BigInt value to u64: `{self:?}`: {err:?}"
87                ))
88            })?)
89        } else {
90            Ok(self
91                .as_f64()
92                .ok_or_else(|| Error::WrongType(format!("value is not a number ({self:?})")))?
93                as u64)
94        }
95    }
96
97    fn try_as_vec_u8(&self) -> Result<Vec<u8>, Error> {
98        if self.is_string() {
99            let hex_string = self.as_string().unwrap();
100            let len = hex_string.len();
101            if len == 0 {
102                Ok(vec![])
103            } else if len & 0x1 == 1 {
104                Err(Error::HexStringNotEven(hex_string))
105            } else {
106                let mut vec = vec![0u8; hex_string.len() / 2];
107                faster_hex::hex_decode(hex_string.as_bytes(), &mut vec)?;
108                Ok(vec)
109            }
110        } else if self.is_object() {
111            let array = Uint8Array::new(self);
112            let vec: Vec<u8> = array.to_vec();
113            Ok(vec)
114        } else {
115            Err(Error::WrongType(
116                "value is not a hex string or an array".to_string(),
117            ))
118        }
119    }
120}
workflow_wasm/extensions/jsvalue.rs

workflow_wasm/extensions/
jsvalue.rs
