fix(codegen): drop redundant space after export default when minifying#23024
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Addressed the P2 review (TS default interfaces): added the missing |
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The TS default-interface break was already fixed in the latest commit: |
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…ing (#23024) ## What Found with a self-written whitespace analyzer (for each space in oxc's minified output, remove it and check the result still canonicalizes to the same AST — if so the space was non-optimal). The most common hit: `ExportDefaultDeclaration` printed `"export default "` with an unconditional trailing space, kept before non-identifier values when minifying: | Input | Before | After | | --- | --- | --- | | `export default {a:1}` | `export default {a:1}` | `export default{a:1}` | | `export default [1]` | `export default [1]` | `export default[1]` | | `export default (a,b)` | `export default (a,b)` | `export default(a,b)` | | `export default "s"` | `export default "s"` | ``export default`s` `` | ## Fix Use a soft space (kept when pretty-printing) and let the value insert a hard space only before an identifier-like token — matching how `return` already works, and esbuild's `SExportDefault` printer (`print("export default")` + `printSpace()`). Spaces that are required are preserved: `export default function(){}`, `export default 5`, `export default foo`, `export default class C{}`. ### TypeScript Exposed a latent bug: `TSInterfaceDeclaration` printed `interface` without a `print_space_before_identifier()` guard, so `export default interface I {}` would have minified to `export defaultinterface`. Added the guard (same fix as #23013 for enums). `export default interface`, `export default abstract class`, and `export default <const>x` all verified to round-trip. Pretty-print output is unchanged. Codegen (115) and minifier (506) suites pass.
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### 💥 BREAKING CHANGES - ee4dc73 ast: [**BREAKING**] Add `#[non_exhaustive]` to AST nodes (#23046) (overlookmotel) - 4c35362 ast: [**BREAKING**] Add `AstBuilder::template_element_escape_raw` and `template_element_escape_raw_with_lone_surrogates` methods (#23047) (overlookmotel) ### 🚀 Features - b846ab2 react_compiler: Integrate the Rust port of the React Compiler (#22942) (Boshen) - 5b8dd68 parser: Report TS1255 for invalid class definite assertions (#22917) (camc314) - 85efabf semantic: Make building the class table optional, off by default (#22862) (Boshen) ### 🐛 Bug Fixes - 556acdc codegen: Parenthesize TS-cast assignment targets (#23112) (Boshen) - 37169ff codegen: Don't emit space between postfix `--` and `>` when minifying (#23036) (Boshen) - a4b1bf7 codegen: Drop redundant whitespace in minified TypeScript output (#23038) (Boshen) - cf53285 parser: Report reserved type-declaration names in the parser (#23035) (Boshen) - 4e44969 ast: Fix UB in `escape_template_element_raw` (#23052) (overlookmotel) - c543154 parser: Report comma operator in JSX expression in the parser (#23030) (Boshen) - 325c94f codegen: Tighten conditional-type and constructor-type whitespace when minifying (#23033) (Boshen) - 95dd3a2 parser: Report `import type` alias to a non-external reference in the parser (#23032) (Boshen) - 90180b8 codegen: Drop space after `:` in function return type when minifying (#23028) (Boshen) - 6da876e parser: Report `abstract` private class field in the parser (#23029) (Boshen) - 28467ce codegen: Don't emit space before a postfix update operand when minifying (#23027) (Boshen) - cb29926 codegen: Drop redundant space after `export default` when minifying (#23024) (Boshen) - 62965ae codegen: Drop redundant space after `else` when minifying (#23025) (Boshen) - 989230a parser: Report compound assignment to non-simple target in the parser (#23022) (Boshen) - 06f367c parser: Report `super.#field` private access in the parser (#23014) (Boshen) - 184edef codegen: Print space before `const`/`declare` enum modifier (#23013) (Boshen) - 4d722e0 parser: Report duplicate switch `default` clause in the parser (#23012) (Boshen) - 597ed85 codegen: Parenthesize `let`/`async` for-of head target (#23008) (Boshen) - 8b631bf codegen: Remove stray space before mapped type value colon (#23010) (Boshen) - c08407e codegen: Don't over-parenthesize `in` inside an arrow in a for-init (#23009) (Boshen) - 600cd6f codegen: Parenthesize lower-precedence `TSInstantiationExpression` operand (#23007) (Boshen) - 187e1a5 codegen: Don't leak space after comment-only JSX expression container (#23006) (Boshen) - 294c473 codegen: Don't over-parenthesize `TSTypeAssertion` operand (#23004) (Boshen) - 786d96f codegen: Give `TSTypeAssertion` unary precedence (#23002) (Boshen) - 1295882 parser: Report `new.target` and `import.meta` syntax errors in the parser (#23003) (Boshen) - d727b6b codegen: Parenthesize `await` expression as base of `**` (#23001) (Boshen) - 67dfa08 codegen: Keep parentheses around `new` callees containing a call (#22997) (Boshen) - 17e7cf3 parser: Disallow unerasable `as`/`satisfies` assertions (#22986) (Boshen) - beb46d3 parser: Commit to module goal on decorated exports (#22941) (Boshen) - 49e63f7 isolated-declarations: Require annotations for satisfies initializers (#22898) (camc314) - 8c93601 isolated-declarations: Allow unknown enum initializer in non-const enum (#22900) (camc314) ### ⚡ Performance - 7d89909 parser: Peek instead of lookahead for yield disambiguation (#23071) (Boshen) - bf872f0 parser: Skip arrow lookahead for a parenthesized literal (#23070) (Boshen) - d19fc54 parser: Guard type-argument speculation behind an angle-token check (#23069) (Boshen) - 8eb5507 parser: Skip redundant member-rest re-scan on call entry (#23068) (Boshen) - 883dfc1 parser: Skip parse_call_expression_rest when no call follows (#23063) (Boshen) - b171153 parser: Peek before the await-using lookahead (#23059) (Boshen) - 56f21bd parser: Use peek_token for the TS `asserts` type predicate (#23058) (Boshen) - 68805ac parser: Use peek_token instead of checkpoint/rewind for single-token decisions (#23056) (Boshen) - 1f9d8eb ast: `AstBuilder::template_element_escape_raw` avoid allocation if no escape required (#23053) (overlookmotel) - 502b04d semantic: Move cold function redeclaration handling into `#[cold]` function (#22973) (overlookmotel) ### 📚 Documentation - 275d318 napi/minifier: Point `target` to oxc docs (#23102) (camc314) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
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What
Found with a self-written whitespace analyzer (for each space in oxc's minified output, remove it and check the result still canonicalizes to the same AST — if so the space was non-optimal). The most common hit:
ExportDefaultDeclarationprinted"export default "with an unconditional trailing space, kept before non-identifier values when minifying:export default {a:1}export default {a:1}export default{a:1}export default [1]export default [1]export default[1]export default (a,b)export default (a,b)export default(a,b)export default "s"export default "s"export default`s`Fix
Use a soft space (kept when pretty-printing) and let the value insert a hard space only before an identifier-like token — matching how
returnalready works, and esbuild'sSExportDefaultprinter (print("export default")+printSpace()).Spaces that are required are preserved:
export default function(){},export default 5,export default foo,export default class C{}.TypeScript
Exposed a latent bug:
TSInterfaceDeclarationprintedinterfacewithout aprint_space_before_identifier()guard, soexport default interface I {}would have minified toexport defaultinterface. Added the guard (same fix as #23013 for enums).export default interface,export default abstract class, andexport default <const>xall verified to round-trip.Pretty-print output is unchanged. Codegen (115) and minifier (506) suites pass.