the.com/callback

A promise with amnesia — it forgets everything except what you told it to remember.

means A function you hand to another piece of code, to be run later once some task or event finishes.

from A straightforward compound of 'call' (to invoke a function) and 'back' (returning control to the caller) — programming jargon that emerged as languages started treating functions as values you could pass around, letting code say 'do this, then call me back when you're done.' The term also echoes the older, non-technical sense of 'return a phone call,' which likely reinforced the name once programmers needed a word for 'I'll get back to you.'

core idea
function passed as data, called later by someone else
js origin
became famous because browsers hate waiting
dark side
too many nested ones create callback hell
modern fix
promises and async await exist to escape it
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