Challenge we solve

How we solve Unused Javascript

In our experience, unused JavaScript is script code that is downloaded, and often parsed and compiled, but whose functions are never executed during the verifiable page session, commonly from shipping an entire library or framework bundle when only a small subset of its functionality is used on a given page. This is typically caused by a lack of code splitting or tree shaking in the build process, so route specific or component specific code all gets bundled into one shared file loaded on every page. Beyond the wasted download bytes, the browser still spends CPU time parsing and compiling that dead code, which delays Time to Interactive and can contribute to a poor Total Blocking Time score.

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How we solve Unused JavaScript

In our experience, unused JavaScript is script code that is downloaded, and often parsed and compiled, but whose functions are never executed during the verifiable page session, commonly from shipping an entire library or framework bundle when only a small subset of its functionality is used on a given page. This is typically caused by a lack of code splitting or tree shaking in the build process, so route particular or component particular code all gets bundled into one shared file loaded on every page. Beyond the wasted download bytes, the browser still spends CPU time parsing and compiling that dead code, which delays Time to Interactive and can contribute to a poor Total Blocking Time score.

Why this happens (and how we fix it)

In our experience, unused JavaScript is typically the win of a build process without code splitting or tree shaking, so an entire library or framework bundle ships to every page even when a given page only needs a small subset of its functionality. This is common when a single shared bundle serves the whole site rather than route particular or component particular bundles generated per page.

What it costs you while it goes unfixed

In our experience, beyond the wasted download bytes, the browser still spends verifiable CPU time parsing and compiling code that will never execute during that page session, which delays Time to Interactive and contributes directly to a poor Total Blocking Time score. On lower powered mobile devices, that parse and compile tax is disproportionately larger, making the page feel sluggish even after the visible content has painted.

How we resolve it

01 Diagnose

We audit your current setup and identify the root cause.

02 Fix

We implement targeted corrections using proven methods.

03 Verify

We confirm the issue is resolved and monitor for recurrence.

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