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denoland-deno/cli/napi/README.md
Ikko Ashimine 10c3c0ee57
chore(napi): fix typo in README.md (#16414)
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# napi
This directory contains source for Deno's Node-API implementation. It depends on
`napi_sym` and `deno_napi`.
- [`async.rs`](./async.rs) - Asyncronous work related functions.
- [`env.rs`](./env.rs) - Environment related functions.
- [`js_native_api.rs`](./js_native_api.rs) - V8/JS related functions.
- [`thread_safe_function.rs`](./threadsafe_functions.rs) - Thread safe function
related functions.
## Adding a new function
Add the symbol name to
[`cli/napi_sym/symbol_exports.json`](../napi_sym/symbol_exports.json).
```diff
{
"symbols": [
...
"napi_get_undefined",
- "napi_get_null"
+ "napi_get_null",
+ "napi_get_boolean"
]
}
```
Determine where to place the implementation. `napi_get_boolean` is related to JS
values so we will place it in `js_native_api.rs`. If something is not clear,
just create a new file module.
See [`napi_sym`](../napi_sym/) for writing the implementation:
```rust
#[napi_sym::napi_sym]
pub fn napi_get_boolean(
env: *mut Env,
value: bool,
result: *mut napi_value,
) -> Result {
// ...
Ok(())
}
```
Update the generated symbol lists using the script:
```
deno run --allow-write tools/napi/generate_symbols_lists.js
```
Add a test in [`/test_napi`](../../test_napi/). You can also refer to Node.js
test suite for Node-API.
```js
// test_napi/boolean_test.js
import { assertEquals, loadTestLibrary } from "./common.js";
const lib = loadTestLibrary();
Deno.test("napi get boolean", function () {
assertEquals(lib.test_get_boolean(true), true);
assertEquals(lib.test_get_boolean(false), false);
});
```
```rust
// test_napi/src/boolean.rs
use napi_sys::Status::napi_ok;
use napi_sys::ValueType::napi_boolean;
use napi_sys::*;
extern "C" fn test_boolean(
env: napi_env,
info: napi_callback_info,
) -> napi_value {
let (args, argc, _) = crate::get_callback_info!(env, info, 1);
assert_eq!(argc, 1);
let mut ty = -1;
assert!(unsafe { napi_typeof(env, args[0], &mut ty) } == napi_ok);
assert_eq!(ty, napi_boolean);
// Use napi_get_boolean here...
value
}
pub fn init(env: napi_env, exports: napi_value) {
let properties = &[crate::new_property!(env, "test_boolean\0", test_boolean)];
unsafe {
napi_define_properties(env, exports, properties.len(), properties.as_ptr())
};
}
```
```diff
// test_napi/src/lib.rs
+ mod boolean;
...
#[no_mangle]
unsafe extern "C" fn napi_register_module_v1(
env: napi_env,
exports: napi_value,
) -> napi_value {
...
+ boolean::init(env, exports);
exports
}
```
Run the test using `cargo test -p test_napi`.