Array

The Array utilities are implemented as a single-function module that exports the flatMap function for recursive array flattening operations.

flatMap

The flatMap function implements recursive flattening of nested object arrays with full TypeScript type safety:

export const flatMap = <
  T extends Record<string, any>,
  K extends Extract<keyof T, string>
>(
  resource: T[],
  key: K
): Array<Omit<T, K>>

Parameters:

resource: Array of objects containing nested arrays
key: String key identifying the property containing nested arrays

Returns: Flattened array with the specified key omitted from all objects

Input Structure Example:

Live Editor

function () {
  const resource = [
    {
      id: 1,
      name: "Item 1",
      children: [
        { id: 2, name: "Item 1.1", children: [] },
        {
          id: 3,
          name: "Item 1.2",
          children: [{ id: 4, name: "Item 1.2.1", children: [] }],
        },
      ],
    },
  ];

  const result = UtilityWrapper.flatMap(resource, "children");

  return (
    <>
      <div>Result: </div>
      <div>{JSON.stringify(result)}</div>
    </>
  );
}

Result

Flexible Key Support

The function supports any string key name for nested arrays:

// Works with "children" key
flatMap(treeData, "children");

// Works with "nodes" key
flatMap(nodeData, "nodes");

// Works with any custom key
flatMap(customData, "subcategories");

flatMap​

flatMap