This change sorts the module factories under Turbopack chunks based on their identifiers, referencing Webpack: https://github.com/webpack/webpack/blob/main/lib/util/comparators.js#L312-L319

This modification can achieve approximately 100% actual size reduction for some Turbopack build artifacts (the improvement is more significant in larger projects):

Before:

After:

The principle here is that (I haven't yet created a minimal reproducible demo), Umi's SPA applications import route paths via dynamic imports:

• Route A asynchronously loads modules [X, Y, Z]
• Route B asynchronously loads modules [Z, X, Y]

Then, when generating chunks:

• modules = [X, Y, Z] -> ident hash = abc123 -> chunk_abc123.js
• modules = [Z, X, Y] -> ident hash = def456 -> chunk_def456.js

However, the module content of these two chunks is actually identical; essentially, they are two identical chunks. Therefore, we directly sort the modules under modules based on moduleId or similar criteria, ensuring that the modules within the chunk remain stable:

• modules = [X, Y, Z] → sort → [X, Y, Z] → ident hash = abc123 → chunk_abc123.js
• modules = [Z, X, Y] → sort → [X, Y, Z] → ident hash = abc123 → chunk_abc123.js

This way, when generating the chunk, it will be treated as a single chunk, thus saving a significant amount of chunk size overhead.

In practice, this should theoretically not affect the existing code logic, because currently it only sorts the modules of the JS chunk, but the actual code execution order is still determined by the dependencies in the dependency graph. Similarly, it will not affect module merging.

Here's a Webpack example:

// index.js
import "./module-a.js";
import "./module-c.js";
import "./module-d.js";
import "./module-b.js";

console.log("main");

// module-a.js
console.log("module a");

// module-b.js
console.log("module b");

// module-c.js
console.log("module c");

// module-d.js
console.log("module d");

When Webpack generates the index.js chunk, regardless of whether the import order is a, b, c, d or a, c, b, d, the corresponding module sorting is:

The modules are sorted according to their module chunk ID names (a->b->c->d), so this should also be applicable to Turbopack.

Related issue: utooland/utoo#2477