wasm-bindgen/tests/wasm/option.js

const assert = require('assert');
const wasm = require('wasm-bindgen-test.js');

class MyType {}

exports.MyType = MyType;

exports.take_none_byval = function(x) {
  assert.strictEqual(x, undefined);
};
exports.take_some_byval = function(x) {
  assert.ok(x !== null && x !== undefined);
  assert.ok(x instanceof MyType);
};
exports.return_undef_byval = function() { return undefined; };
exports.return_null_byval = function() { return null; };
exports.return_some_byval = function(x) {
  return new MyType();
};

exports.test_option_values = function() {
  wasm.rust_take_none_byval(null);
  wasm.rust_take_none_byval(undefined);
  wasm.rust_take_some_byval(new MyType());
  assert.strictEqual(wasm.rust_return_none_byval(), undefined);
  const x = wasm.rust_return_some_byval();
  assert.ok(x !== null && x !== undefined);
  assert.ok(x instanceof MyType);
};