retrieve.go

package funk

import (
	"reflect"
	"strings"
)

// Get retrieves the value at path of struct(s).
func Get(out interface{}, path string) interface{} {
	result := get(reflect.ValueOf(out), path)

	if result.Kind() != reflect.Invalid {
		return result.Interface()
	}

	return nil
}

func get(value reflect.Value, path string) reflect.Value {
	if value.Kind() == reflect.Slice || value.Kind() == reflect.Array {
		var resultSlice reflect.Value

		length := value.Len()

		for i := 0; i < length; i++ {
			item := value.Index(i)

			resultValue := get(item, path)

			if resultValue.Kind() == reflect.Invalid {
				continue
			}

			resultType := resultValue.Type()

			if resultSlice.Kind() == reflect.Invalid {
				resultType := reflect.SliceOf(resultType)

				resultSlice = reflect.MakeSlice(resultType, 0, 0)
			}

			resultSlice = reflect.Append(resultSlice, resultValue)
		}

		// if the result is a slice of a slice, we need to flatten it
		if resultSlice.Type().Elem().Kind() == reflect.Slice {
			return flattenDeep(resultSlice)
		}

		return resultSlice
	}

	parts := strings.Split(path, ".")

	for _, part := range parts {
		value = redirectValue(value)
		kind := value.Kind()

		if kind == reflect.Invalid {
			continue
		}

		if kind == reflect.Struct {
			value = value.FieldByName(part)
			continue
		}

		if kind == reflect.Slice || kind == reflect.Array {
			value = get(value, part)
			continue
		}
	}

	return value
}