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Dead code elimination is related to but distinct from tree shaking - it also means that unused code branches get removed, for example constants like NODE_ENV get replaced with a static value, and if you have a static condition that always results to true, the else branch is removed.

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In my book that's all covered by the term 'dead code elimination', e.g. removing (or not including in the first place) any code that can be statically proven to be unreachable at runtime. Some JS minifiers (like Google's Closure) can do the same thing in Javascript on the AST level (AFAIK Closure essentially breaks the input code down into an AST, then does static control flow analysis on the AST, removes any unreachable parts, and finally compiles the AST back into minified Javascript). Tree-shaking without this static control flow analysis doesn't make much sense IMHO since it wouldn't be able to remove things like a dynamic import inside an if that always resolves to true or false.

Yep, that's how it works - you first perform dead code elimination and then tree shaking exactly because it wouldn't remove everything otherwise. Agreed that you need both done one after another in most cases; however you can usually disable either one in bundler configuration and it's a separate step.

https://makojs.dev/blog/mako-tree-shaking explains how mako do the tree shaking stuff, but in Chinese.

In my two cents, the tree shaking is more focus on removing unused exports in ES module at top level. it's a mixing with Dead code elimination and link time optimization.

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