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Go Reference Coverage Status GoReportCard Mentioned in Awesome Go

Deep walk by object with reflection. Walker.Walk(v interface{}) call callback function for v object, every field if it struct, every item for slice/array and every key and item for map object. It walk for object recursive and call callback for every object in tree.

It has loop protection - for not hang on cycled structured, protection can be disabled if need.

WalkInfo - struct, send as argument to callback function include:

  • Value - reflection.Value object for read/manipulate with it.
  • DataPointer - direct pointer to underly data, for example - pointer to bytes under string, ot pointer to data under slice. It is danger to manipulate it, but can userful for example for compare objects.
  • Parent - parent of the value in travel tree
  • and some other hints about Value
    package main

    import ""

    func main() {
		type S struct {
			Val1  int
			Slice []string

		val := S{
			Val1:  2,
			Slice: []string{"hello", "world"},
		_ = New(func(info *WalkInfo) error {
			return nil

		// Output:
		// {2 [hello world]}
		// 2
		// [hello world]
		// hello
		// world