Crate utility_types

Expand description

§utility types

This crate use proc-macro to realize several utility types of Typescript in Rust.

macro	Typescript Utility Type
Partial	Partial<Type>
Pick	Pick<Type, Keys>
Omit	Omit<Type, Keys>
Extract	Extract<Type, Union>
Exclude	Exclude<UnionType, ExcludedMembers>

§Example

Here is an example of how to use this crate.

use utility_types::{Omit, Partial, Pick, Required};
#[derive(Clone, Partial, Required, Pick, Omit)]
#[partial(ident = PartialFoo, derive(Debug, PartialEq), forward_attrs())]
#[required(ident = RequiredFoo, derive(Debug, PartialEq), forward_attrs())]
#[pick(arg(ident = PickAB, fields(a, b), derive(Debug, PartialEq)), forward_attrs())]
#[omit(arg(ident = OmitCD, fields(c, d), derive(Debug, PartialEq)), forward_attrs())]
pub struct Foo {
    a: u8,
    b: Option<u8>,
    c: Option<Vec<u8>>,
}

The above code will generate the following code.

#[derive(Debug, PartialEq)]
pub struct PartialFoo {
    a: Option<u8>,
    b: Option<Option<u8>>,
    c: Option<Option<Vec<u8>>>,
}
#[derive(Debug, PartialEq)]
pub struct RequiredFoo {
    a: u8,
    b: u8,
    c: Vec<u8>,
}
#[derive(Debug, PartialEq)]
pub struct PickAB {
    a: u8,
    b: Option<u8>,
}
#[derive(Debug, PartialEq)]
pub struct OmitCD {
    a: u8,
    b: Option<u8>,
}

Some useful traits are also generated:

From<Foo> for PartialFoo, PickAB, OmitCD
From<PartialFoo> for Foo

§Forwarding Attributes

To use this crate with other crates that need attributes, you can use the forward_attrs attribute to control which attributes are forwarded to the generated struct or enum.

use serde::{Deserialize, Serialize};
use utility_types::Omit;

#[derive(Debug, PartialEq, Serialize, Deserialize, Omit)]
#[omit(
    arg(
        ident = OmitCD,
        fields(c, d),
        derive(Debug, PartialEq, Serialize, Deserialize),
        forward_attrs(serde)
    )
)]
#[serde(rename_all = "UPPERCASE")]
pub struct Foo {
    a: u8,
    b: Option<u8>,
    c: Option<Vec<u8>>,
}

let omit_cd: OmitCD = serde_json::from_str(r#"{"A": 1, "B": 2}"#).unwrap();
assert_eq!(omit_cd, OmitCD { a: 1, b: Some(2) });

The behavior of the forward_attrs attribute is as follows:

If not provided, all attributes are forwarded by default.
If provided with a list of attributes, only the specified attributes are forwarded.
- For example, forward_attrs(doc, serde) will forward only doc and serde.
- If provided with only * (forward_attrs(*)), all attributes are forwarded.
- If provided with an empty list (forward_attrs()), no attributes are forwarded.
If provided with a list inside not(), all attributes except the specified attributes are forwarded.
- For example, forward_attrs(not(serde)) will forward all attributes except serde.

§Known Issue

Currently I don’t analyze which generic is used in the generated struct or enum. So rustc will complain if the field with generic is not included in the generated struct or enum.

Derive Macros§