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AWS Lambda Quick Start Guide

You're reading from   AWS Lambda Quick Start Guide Learn how to build and deploy serverless applications on AWS

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Product type Paperback
Published in Jun 2018
Publisher Packt
ISBN-13 9781789340198
Length 184 pages
Edition 1st Edition
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Author (1):
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Markus Klems Markus Klems
Author Profile Icon Markus Klems
Markus Klems
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Toc

Programming a Lambda function with Node.js

Now, let's learn a little bit more about programming Lambda functions with Node.js. We are going to take a closer look at the function handler, and in particular its arguments, that is:

  • Event objects
  • Context objects
  • Callback objects

Open the handler.js file and delete the code that's in the function body. One way to learn about the event and context object would be to log them out on the console:

'use strict';
module.exports.hello = (event, context, callback) => {
console.log('event is', event);
};

Let's see what this gives us.

I am invoking the function locally to see what the output is with the function name set as hello:

sls invoke local -f hello
event is

Ok, my event, apparently, is null. Let's see what the context is, as shown next:

module.exports.hello = (event, context, callback) =&gt...
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