Function copyWithSetImpl

packages/react-reconciler/src/ReactFiberReconciler.js:686–700

(
    obj: Object | Array<any>,
    path: Array<string | number>,
    index: number,
    value: any,
  )

  };

  const copyWithSetImpl = (
    obj: Object | Array<any>,
    path: Array<string | number>,
    index: number,
    value: any,
  ): $FlowFixMe => {
    if (index >= path.length) {
      return value;
    }
    const key = path[index];
    const updated = isArray(obj) ? obj.slice() : {...obj};
    // $FlowFixMe[incompatible-use] number or string is fine here
    updated[key] = copyWithSetImpl(obj[key], path, index + 1, value);
    return updated;
  };

  const copyWithSet = (
    obj: Object | Array<any>,