How to curry a function in JavaScript
Łukasz Holeczek
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Function currying transforms a function that takes multiple arguments into a series of functions that each take a single argument. As the creator of CoreUI with extensive experience in JavaScript development since 2000, I’ve used currying to create more flexible and reusable function compositions. From my expertise, the most practical approach is to return a new function that captures arguments until all required parameters are provided. This technique enables partial application and creates more modular, testable code.
Transform a multi-argument function into a series of single-argument functions using closures.
function curry(fn) {
return function curried(...args) {
if (args.length >= fn.length) {
return fn.apply(this, args)
}
return function(...nextArgs) {
return curried.apply(this, args.concat(nextArgs))
}
}
}
Here the curry function takes any function fn and returns a new curried version. The curried function checks if enough arguments have been provided using args.length >= fn.length. If sufficient arguments are available, it executes the original function. Otherwise, it returns another function that collects more arguments and calls itself recursively with the combined arguments.
Best Practice Note:
This is the same pattern we use in CoreUI’s configuration functions for creating flexible component builders. Currying is particularly useful for creating specialized versions of generic functions and building function pipelines.
