bucklescript types for aws-lambda
npm install @ahrefs/bs-aws-lambdabs-aws-lambda is a set of types to use when creating AWS
lambda handlers.
Those types are inspired by the@types/aws-lambda
package with typescript types.
``
yarn add @ahrefs/bs-aws-lambda
or to follow the master version:
`
yarn add https://github.com/ahrefs/bs-aws-lambda.git
Add @ahrefs/bs-aws-lambda to the bs-dependencies of bsconfig.json.
Then when you create a function handler for a lambda, you can annotate
it with one of AwsLambda.Scheduled.handler,AwsLambda.Dynamodb.streamHandler, AwsLambda.Sns.handler, etc. This
way you are sure to expose a function which respect the signature
expected by Lambda and you get types information for all the
parameters this function will receive.
A full example is documented
here. It
is using the sources from the example directory.
Simple echo function for the API Gateway. This might seem a little
verbose compare to a typescript version. But using this package, you
are sure to handle all the possible cases where a value is actually
null or base64 encoded. Plus the returned object given to the callback
will always have the expected fields and types.
`reasonPlain({|{"status": "no body available in the request"}|}),
let handler: AwsLambda.APIGatewayProxy.handler =
(event, _context, cb) => {
open AwsLambda.APIGatewayProxy;
let parameter =
event
|. Event.queryStringParameters
|> Js.Option.andThen((. params) => Js.Dict.get(params, "userid"));
switch (parameter) {
| Some(userid) => Js.log2("executing lambda for", userid)
| None => Js.log("executing lambda for anonymous user")
};
let result =
switch (event |. Event.body) {
| None =>
Js.log("error: no body available in the request");
result(
~body=
~statusCode=400,
(),
);
| Some(body) =>
Result.make(~statusCode=200, ~body, ~isBase64Encoded=event |. Event.isBase64Encoded, ())
};
cb(Js.null, result);
Js.Promise.resolve();
};
``
The typescript equivalent of the type annotation is actually more verbose:
`typescript``
export const handle: Lambda.APIGatewayProxyHandler = async (
event: Lambda.APIGatewayEvent,
context: Lambda.Context,
cb: Lambda.APIGatewayProxyCallback) => {
}