This question comes up quite often in Frontend interviews, and it is frequently asked on projects that were started 5-7 years ago. That was exactly the time when functional programming was at its peak in the JS world, and libraries like Ramda.js were used very often.
Currying is a technique in functional programming where a function that takes multiple arguments is transformed into a chain of functions, each of which takes one (or more) arguments and returns the next function.
Let's look at an example
We have a function sum, and without Currying we have to pass all three arguments at once for the function to work correctly. With Currying, however, we can pass the arguments partially. For example, first pass a, after which the function does not execute but returns another function that accepts b and c. Then we can either pass b and c or only b, in which case a function that accepts c is returned. Only after c is passed does the function execute.
An example of a native implementation of Currying is the bind function in JavaScript. Technically, it is not quite the same thing, but rather a simpler version of it: partial application. Nevertheless, bind clearly shows how powerful this technique is and what problems it can solve.
For those who want to dig deeper into functional programming, I recommend starting with Ramda.js - https://ramdajs.com/. While reading the documentation, it is worth going through the various concepts you will come across with ChatGPT.