garbage collect the AST while outputting code #1189
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fabiosantoscode
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fabiosantoscode
commented
Apr 30, 2022
| @@ -2278,7 +2269,6 @@ var AST_ClassExpression = DEFNODE("ClassExpression", null, function AST_ClassExp | |||
| this.extends = props.extends; | |||
| this.properties = props.properties; | |||
| this.variables = props.variables; | |||
| this.functions = props.functions; | |||
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This property isn't used anymore, as it was all merged into .variables
fabiosantoscode
commented
Apr 30, 2022
| node.block_scope.enclosed = undefined; | ||
| node.parent_scope = undefined; | ||
| } | ||
| }); |
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This is done before the options.sourceMap.includeSources check below, which increases memory usage.
jridgewell
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Apr 30, 2022
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Currently, while the code is being printed, the whole AST is in memory.
The AST is really heavy, and people rightfully complain about memory usage (#164, #283)
The NextJS documentation even mentions the issue being exacerbated by source maps, though I'm not sure it's just about Terser
To avoid using more RAM, delete the AST as we go through it.
The new internal format option
_destroy_astdeletes chunks of the AST during the output phase, and it's automatically set by minify.js.The chunks being deleted are functions, as they can get pretty large. I'm pretty sure this doesn't delete everything that should be deleted, but memory reported actually goes down while outputting.