What is a common memory leak pattern with closures in JavaScript?
Pushing closures into an array or map, where each closure captures a large object. As the collection grows, each entry keeps its large object alive, and the memory grows unbounded. Remove entries when they are no longer needed.
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More FAQs in Garbage Collection and Block Scope in JavaScript
When a block ends, its lexical environment is eligible for GC (unless a closure keeps it alive). This lets the GC free block-scoped variables sooner than function-scoped var variables, which stay alive until the function returns.
Because var is function-scoped, not block-scoped. A var inside a block leaks to the enclosing function scope and stays alive until the function returns, even if the block has ended. let and const are freed when the block ends.
Yes. A closure keeps a reference to its lexical environment. As long as the closure exists, the closed-over variables cannot be garbage collected. This is a common source of memory leaks.
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