components-contrib/internal/config/prefix.go

54 lines
1.2 KiB
Go

package config
import (
"strings"
"unicode"
)
func PrefixedBy(input interface{}, prefix string) (interface{}, error) {
normalized, err := Normalize(input)
if err != nil {
// The only error that can come from normalize is if
// input is a map[interface{}]interface{} and contains
// a key that is not a string.
return input, err
}
input = normalized
if inputMap, ok := input.(map[string]interface{}); ok {
converted := make(map[string]interface{}, len(inputMap))
for k, v := range inputMap {
if strings.HasPrefix(k, prefix) {
key := uncapitalize(strings.TrimPrefix(k, prefix))
converted[key] = v
}
}
return converted, nil
} else if inputMap, ok := input.(map[string]string); ok {
converted := make(map[string]string, len(inputMap))
for k, v := range inputMap {
if strings.HasPrefix(k, prefix) {
key := uncapitalize(strings.TrimPrefix(k, prefix))
converted[key] = v
}
}
return converted, nil
}
return input, nil
}
// uncapitalize initial capital letters in `str`.
func uncapitalize(str string) string {
if len(str) == 0 {
return str
}
vv := []rune(str) // Introduced later
vv[0] = unicode.ToLower(vv[0])
return string(vv)
}