Advanced Recursive Function to Deeply Flatten and Transform Nested Arrays in JavaScript
Create a highly optimized recursive function that accepts an arbitrarily nested array structure containing numbers and arrays, deeply flattens it into a single-level array, and applies a transformation function to each number. This challenge tests mastery of recursion, performance optimization, and functional programming in JavaScript.
Challenge prompt
Build a function named `deepFlattenTransform` that takes two parameters: (1) an arbitrarily nested array containing numbers or further nested arrays, and (2) a callback function to transform each number. The function should recursively flatten all levels of nesting into a single array, applying the callback transformation to each numeric value before including it in the output array. Your implementation must be efficient and capable of handling deeply nested and large inputs without exceeding the call stack or causing significant performance degradation.
Guidance
- • Use recursion to traverse nested arrays, but consider tail call optimization techniques or iterative solutions if your environment supports them to avoid stack overflows.
- • Apply the callback function as you extract each number from the nested structure before adding it to the result array.
- • Optimize for performance when handling large and deeply nested arrays, avoiding unnecessary array concatenations or copying.
- • Ensure your function gracefully handles edge cases such as empty arrays, arrays with non-numeric values, and deeply nested empty arrays.
Hints
- • Consider using a helper function or inner recursive function to maintain clean code organization.
- • Avoid using Array.prototype.flat(Infinity), as it might not allow easy insertion of the transformation step.
- • Think about using iterative methods with your own stack if recursion depth is a concern in your environment.
Starter code
function deepFlattenTransform(nestedArray, transformFn) {
// Your code here
}Expected output
deepFlattenTransform([1, [2, [3, [4]], 5]], x => x * 2) // returns [2, 4, 6, 8, 10]
Core concepts
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