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Lambda: All Functions have a Light Bundle

Lambda functions are deployed to AWS with their dependencies in a bundle. The size of this bundle impacts the cold start of your function. The lighter the bundle, the faster the cold start.

Needless to say, smaller bundles will help you respect AWS Quotas.

Suggestion Actions​

1. Refactor your code to depend on fewer or lighter dependencies​

If you use the Serverless Framework, the Serverless Analyze Bundle Plugin will help you find heavy dependencies.

2. Configure your bundler​

If you use the Serverless Framework and the plugin serverless-esbuild, this is the configuration that we recommend:

// serverless.ts
const serverlessConfiguration: AWS = {
  ...
  custom: {
    ...
    esbuild: {
      ...
      /**
       * Reduce the size of the bundle.
       */
      minify: true,
      /**
       * Keep the names of functions and classes (useful for libraries like `typeorm`).
       */
      keepNames: true,
      /**
       * If you don't care about immutable infrastructure, do not include the AWS SDK in your bundle.
       * The execution environment of your Lambda function has a built-in AWS SDK that you can require at runtime.
       */
      exclude: ['aws-sdk'],
      /**
       * Helps choosing tree-shakable code.
       */
      mainFields: ['module', 'main'],
    },
  },
};

Useful links