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https://github.com/fluencelabs/wasm-bindgen
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9753f9150b
Support the `js_name` attribute on exports as well as imports to allow exporting types as camelCase instead of snake_case, for example. Closes #221
86 lines
1.9 KiB
Markdown
86 lines
1.9 KiB
Markdown
# Customizing import behavior
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The `#[wasm_bindgen]` macro supports a good amount of configuration for
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controlling precisely how exports are exported and what they generate in JS.
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This section is intended to hopefully be an exhaustive reference of the
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possibilities!
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* `readonly` - when attached to a `pub` struct field this indicates that it's
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readonly from JS and a setter will not be generated.
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```rust
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#[wasm_bindgen]
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pub struct Foo {
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pub first: u32,
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#[wasm_bindgen(readonly)]
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pub second: u32,
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}
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```
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Here the `first` field will be both readable and writable from JS, but the
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`second` field will be a `readonly` field in JS where the setter isn't
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implemented and attempting to set it will throw an exception.
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* `constructor` - when attached to a Rust "constructor" it will make the
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generated JS bindings callable as `new Foo()`, for example:
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```rust
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#[wasm_bindgen]
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pub struct Foo {
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contents: u32,
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}
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#[wasm_bindgen]
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impl Foo {
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#[wasm_bindgen(constructor)]
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pub fn new() -> Foo {
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Foo { contents: 0 }
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}
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pub fn get_contents(&self) -> u32 {
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self.contents
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}
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}
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```
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Here this can be used in JS as:
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```js
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import { Foo } from './my_module';
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const f = new Foo();
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console.log(f.get_contents());
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```
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* `js_name` - this can be used to export a different name in JS than what
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something is named in Rust, for example:
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```rust
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#[wasm_bindgen]
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pub struct Foo {
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contents: u32,
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}
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#[wasm_bindgen(js_name = makeFoo)]
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pub fn make_foo() -> Foo {
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Foo { contents: 6 }
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}
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#[wasm_bindgen]
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impl Foo {
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#[wasm_bindgen(js_name = getContents)]
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pub fn get_contents(&self) -> u32 {
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self.contents
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}
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}
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```
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Here this can be used in JS as:
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```js
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import { makeFoo } from './my_module';
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const foo = makeFoo();
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console.log(foo.getContents());
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```
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