test_await_thenables.cjs
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test_await_thenables.cjs
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	function assertEq(name, actual, expected) {
	if (actual !== expected) {
	throw new Error(`${name}: expected ${expected}, got ${actual}`);
	}
	console.log(`ok ${name}`);
	}

	class ProtoThenable {
	constructor(value) {
	this.value = value;
	}
	}

	ProtoThenable.prototype.then = function(resolve, _reject) {
	resolve(this.value);
	};

	class APIPromiseLike {
	constructor(value) {
	this.promise = Promise.resolve([{ ok: true, value }]);
	}

	then(onfulfilled, onrejected) {
	return this.promise.then(
	onfulfilled ? ([result]) => onfulfilled(result.value) : undefined,
	onrejected
	);
	}
	}

	(async function() {
	assertEq('await plain thenable', await {
	then(resolve, _reject) {
	resolve(42);
	}
	}, 42);

	assertEq('await prototype thenable', await new ProtoThenable(99), 99);

	assertEq('await APIPromise-like thenable', await new APIPromiseLike('ok'), 'ok');

	assertEq(
	'Promise.resolve still adopts thenables',
	await Promise.resolve(new ProtoThenable('wrapped')),
	'wrapped'
	);
	})().catch((err) => {
	console.error(err);
	process.exitCode = 1;
	});