extract-const-value: fold arithmetic BinaryExpression and UnaryExpression

[yogeshwaran-c]

What?

Make next build recognize compile-time arithmetic in segment-config exports like

export const revalidate = 60 * 5
export const maxDuration = 60 * 60 * 2

Today these fail with

Unsupported node type "BinaryExpression" at "revalidate".
Read More - https://nextjs.org/docs/messages/invalid-page-config

forcing users to inline the result by hand.

Why?

extract-const-value.ts walks the SWC AST of an exported const initializer and folds it down to a runtime value. It already handled literals (null, boolean, string, number, regexp, template literals with no expressions), Array/Object expressions, the undefined identifier, and TS-only wrappers (as, satisfies, type/const assertions). It had no case for BinaryExpression or UnaryExpression, so any compound expression — even a trivially constant one like 60 * 5 or -42 — bailed out as unsupported.

This is reported as #72365, and a few callsites in the wild use the obvious pattern (e.g. 60 * 60 * 24 for a 1-day revalidate window).

How?

Added cases for BinaryExpression and UnaryExpression, restricted to a small set of pure operators with no side-effect or short-circuit semantics:

• Binary: + - * / % **
• Unary: - + ~

Logical (&&, ||, ??), comparison (<, >, ==, ===, !=, !==, <=, >=), and unary !, typeof, void, delete are intentionally not added — they either short-circuit (which would change what the extractor sees as "the value") or invoke runtime semantics that don't belong in a build-time constant. They keep returning unsupported.

Recursion handles nesting naturally (60 * 60 * 24 → folds left-to-right; 100 + -42 works because -42 is a UnaryExpression(NumericLiteral(42)) per the SWC AST).

Test plan

Added test/unit/extract-const-value.test.ts with 11 cases:

• Plain numeric literal (baseline).
• The exact Next.js 15 - Unsupported "BinaryExpression" error in "revalidate" field for math expressions #72365 regression: 60 * 5.
• Additive BinaryExpression.
• Nested binary (60 * 60 * 24).
• String concat ('edge' + '').
• Unary -42.
• Unary inside binary (100 + -42).
• Exponentiation (2 ** 10).
• Rejection of && (binary).
• Rejection of ! (unary).
• Rejection of 1 + foo — confirms an unfoldable identifier in one operand still propagates the original "Unknown identifier" error rather than getting masked by the new code path.

npx jest test/unit/extract-const-value.test.ts → 11 passed locally.

The test uses the same installBindings() + parseModule setup as the existing parse-page-static-info.test.ts to exercise real SWC parsing.

Fixes #72365

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