46 lines
1.2 KiB
Go
46 lines
1.2 KiB
Go
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package fieldutils
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// MergeFieldMaps takes a slice of field maps,
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// and merges all the key/value pairs into a new single field map.
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//
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// Input order matters: in case two or more maps use the same key,
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// the last one to set that key will have the corresponding value
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// persisted.
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func MergeFieldMaps(maps ...map[string]interface{}) map[string]interface{} {
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// Pre-allocate a map to merge all the maps into,
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// that has at least the capacity equivalent to the number
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// of maps to merge
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result := make(map[string]interface{}, len(maps))
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// Merge all the maps into one;
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// in case of clash, only the last key is preserved
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for _, m := range maps {
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for k, v := range m {
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result[k] = v
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}
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}
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return result
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}
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// FieldMapsToKeys will extract all the field maps keys, avoiding repetitions
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// in case two or more maps contained the same key.
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func FieldMapsToKeys(maps ...map[string]interface{}) []string {
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switch len(maps) {
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case 0:
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return nil
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case 1:
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result := make([]string, 0, len(maps[0]))
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for k := range maps[0] {
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result = append(result, k)
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}
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return result
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default:
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// As we merge all maps into one, we can use this
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// same function recursively, falling back on the `switch case 1`.
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return FieldMapsToKeys(MergeFieldMaps(maps...))
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}
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}
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