Getting the size of a string for napi_get_value_string_utf16 about node-addon-api HOT 8 CLOSED

if I understand it correctly, getting a string with it should be as simple as new Napi::String::String (env, args[0])

If you’re creating your functions using this wrapper API it gets even easier than that. :) Something like this should work:

void Foobar(const CallbackInfo& info) {
  assert(info[0].IsString());
  std::string arg = info[0].As<String>().Utf8Value();
}

void Init(Env env, Object exports, Object module) {
 exports.Set("foobar", Function::New(env, Foobar)); 
}

NODE_API_MODULE(addon, Init)

from node-addon-api.

@addaleax Thank you! That's a lot of code to get a string, to be honest, but NAPI is still more readable than v8 bindings, I guess.

from node-addon-api.

@addaleax I didn't notice that this repository was for a different API :) Google led me here when I was looking for N-API. The wrapper API seems quite nice, if I understand it correctly, getting a string with it should be as simple as new Napi::String::String (env, args[0]) and it can be then converted with std::u16string(). That's nice indeed. Thank you!

from node-addon-api.

You can call napi_get_value_string_utf16 with the buf argument set to NULL – in that case, copied0 would still be filled with the size of the string.

(In your example, sizeof(args[0]) doesn’t seem correct – it will give you the size of args[0] as a pointer, not of the JavaScript value that it refers to.)

from node-addon-api.

@addaleax So in that case I do two calls to napi_get_value_string_utf16, the first one with buf set to NULL to get the size of the string, and the second one get the string itself, correct?

        // where args[0] is a JS string passed into the C++ function
	size_t strSize;
	status = napi_get_value_string_utf16(env, args[0], NULL, NULL, &strSize);
	assert(status == napi_ok);
	char16_t value0[strSize];
	size_t copied0;
	status = napi_get_value_string_utf16(env, args[0], value0, bufSize, &copied0);
	assert(status == napi_ok);

from node-addon-api.

@zandaqo In C++ that should work, yup. :) You don’t need the extra copied0, though, since you already know the string size.

from node-addon-api.

@zandaqo Keep an eye on the C++ wrapper API in this module here (https://www.npmjs.com/package/node-addon-api) – it’s a lot more readable than the raw C APIs exposed by NAPI, and much more so than the V8 API itself.

from node-addon-api.

@addaleax Now that's impressive! It took me some 50 locs of N-API to expose a single function that takes two strings and returns an integer; this API reduces that to mere handful locs. it's almost too easy.

from node-addon-api.