lambda-wrap

LambdaWrap

Simple async function wrapper for AWS lambda and serverless library

• allows using common middlewares (before, catch)
• allows to set common error response format
• supports generator functions using co (optional)

const { lambdaWrap } = require('lambda-wrap');

const wrap = lambdaWrap({
    headers: {
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Credentials': 'true',
    },
    callbackWaitsForEmptyEventLoop: false, // usefull for mongodb
    verboseError: true // include error stack in response (possible to )
    verboseLog: true // include headers and body in error log
});

wrap.before((event) => {
    if (event.body && `${event.headers['content-type']}`.match(/^application\/json/)) {
        event.body = JSON.parse(event.body);
    }
});

// or you can set custom logger
wrap.logger = console;

wrap.finally((error, response) => {
    // close connections or send logs
});

module.exports.myHandler = wrap(async (event) => {

    // return json body
    return {
        body: {
            objectAttribute: true
        }
    };
})

---

API

Classes

lambdaWrap

Functions

error(message, code)

Return new error object.

lambdaWrap

Kind: global class

• lambdaWrap
  • new lambdaWrap([options])
  • ~wrap(fn) ⇒ lambdaHandler
    • .responseHandler
    • .errorResponseHandler
    • .logger
    • .before(fn)
    • .catch(fn)
    • .finally(fn)

new lambdaWrap([options])

lambdaWrap function. You can pass options to override or assign new attributes to event object. For example add custom headers:

const headers = {
  'X-Auth-Token': 'my-token'
};

const wrap = lambdaWrap({ headers });

It returns an instance of LambdaWrap - wrap object. This object can be used for specifying additional properties:

wrap.responseHandler = customResponseFunction;

Finally, wrap object can be used as a function to wrap any generator function and thus create lambda handler:

const handler = wrap(async (event) => {
    return {
        body: 'Hello world'
    };
});

Returns: wrapFn - - the wrap function

Param	Type	Description
[options]	LambdaWrapOptions	Use to override or assign new attributes to event object. E.g. headers.

lambdaWrap~wrap(fn) ⇒ lambdaHandler

Kind: inner method of lambdaWrap
Returns: lambdaHandler - - Lambda handler.

Param	Type	Description
fn	function	Function to be wrapped and used as a lambda handler.

• ~wrap(fn) ⇒ lambdaHandler
  • .responseHandler
  • .errorResponseHandler
  • .logger
  • .before(fn)
  • .catch(fn)
  • .finally(fn)

wrap.responseHandler

Override default response function

Kind: static property of wrap

wrap.errorResponseHandler

Override default error response function

Kind: static property of wrap

wrap.logger

Override default logger object - console. MUST implement log, warn and error methods.

Kind: static property of wrap

wrap.before(fn)

Add new middleware.

Kind: static method of wrap

Param	Type	Description
fn	function	Middleware function.

wrap.catch(fn)

Add new catch.

Kind: static method of wrap

Param	Type	Description
fn	function	Catch function.

wrap.finally(fn)

Add finally method, which will be called after each request

Kind: static method of wrap

Param	Type	Description
fn	function	Middleware function.

error(message, code)

Return new error object.

Kind: global function

Param	Type	Description
message	string	Error message.
code	integer	Error code.