<p>A TypeScript Lambda that calls Claude needs two separate build steps. First, tsc --noEmit checks your types and writes no files. Second, esbuild bundles the TypeScript into a single JavaScript file that Lambda can run. Lambda does not execute TypeScript source, and AWS states that esbuild does not type-check, so a clean esbuild bundle does not prove your code is type-correct. Keeping both steps in your build script is the core of the workflow.</p>
<p>The title promises a "lightning-fast" function. That is a goal for the design, not a result this article measures. The sources consulted do not benchmark this combination of Lambda, esbuild and Claude, so no speed figure appears below. The final section explains how to measure your own deployment.</p>
<h2>How the pieces fit together</h2> As an Amazon Associate I earn from qualifying purchases. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply. What’s actually slowing this PC down? Pick the symptom - the matching free tool is one click away.
<p>The build has three stages, and each has one job:</p>
<ul>
<li><strong>Type check:</strong> <code>tsc –noEmit</code> reads your TypeScript configuration and reports type errors. It produces no output files.</li>
<li><strong>Bundle:</strong> esbuild reads your handler, follows its imports, and writes one JavaScript file, including the packages it uses.</li>
<li><strong>Package and deploy:</strong> you zip the emitted file and point the Lambda handler setting at it.</li>
</ul>
<p>AWS documents this split in its guide to building TypeScript Lambda functions, which also explains the difference between esbuild and Quick Recap
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