diff options
Diffstat (limited to 'src/feature_flags.zig')
| -rw-r--r-- | src/feature_flags.zig | 43 |
1 files changed, 35 insertions, 8 deletions
diff --git a/src/feature_flags.zig b/src/feature_flags.zig index a0db75f79..a01fea7dc 100644 --- a/src/feature_flags.zig +++ b/src/feature_flags.zig @@ -122,15 +122,42 @@ pub const react_server_components = true; pub const help_catch_memory_issues = @import("bun").Environment.allow_assert; -/// Disabled because we need to handle module scope for CJS better. +/// This performs similar transforms as https://github.com/rollup/plugins/tree/master/packages/commonjs /// -/// The current bugs are: -/// - We need to handle name collisions in the top-level due to hoisted functions -/// It breaks when multiple modules bundled together have functions with the -/// same name at the top-level scope. -/// - Cyclical requires need to be a de-optimization. +/// Though, not exactly the same. /// -/// Once fixed, it's a very meaningful bundle size improvement -pub const commonjs_to_esm = false; +/// There are two scenarios where this kicks in: +/// +/// 1) You import a CommonJS module using ESM. +/// +/// Semantically, CommonJS expects us to wrap everything in a closure. That +/// bloats the code. We want to make the generated code as small as we can. +/// +/// To avoid that, we attempt to unwrap the CommonJS module into ESM. +/// +/// But, we can't always do that. When you have cyclical require() or directly +/// mutate exported bindings, we can't unwrap it. +/// +/// However, in the simple case, where you do something like +/// +/// exports.foo = 123; +/// exports.bar = 456; +/// +/// We can unwrap it into +/// +/// export const foo = 123; +/// export const bar = 456; +/// +/// 2) You import a CommonJS module using CommonJS. +/// +/// This is a bit more complicated. We want to avoid the closure wrapper, but +/// it's really difficult to track down all the places where you mutate the +/// exports object. `require.cache` makes it even more complicated. +/// So, we just wrap the entire module in a closure. +/// +/// But what if we previously unwrapped it? +/// +/// In that case, we wrap it again in the printer. +pub const unwrap_commonjs_to_esm = true; pub const boundary_based_chunking = true; |