JavaScript closure is a function that has access to variables in its outer lexical scope, even after the outer function has returned. It's like that annoying coworker who remembers every detail of a conversation from 3 years ago at the company holiday party.

How to use it in a sentence

• Oh great, the new hire used a JavaScript closure to encapsulate the state in that React component - I guess we'll be stuck maintaining that clever code for eternity now.

• Sure, you could use a JavaScript closure to create a private variable, but at Facebook we prefer to just make everything public and let the Metaverse sort it out.

If you actually want to learn more...

• Martin Fowler has a somewhat helpful article on lambdas and closures, if you can get past the pretentious tone and Smalltalk references.

• The Mozilla Developer Network has a painfully detailed explanation of JavaScript closures, complete with interactive examples for those who learn by frantically clicking buttons.

• If you've got half a day to kill, you could slog through this chapter from the "Eloquent JavaScript" book, which covers closures in excruciating detail along with other function esoterica.

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