v1.13.3

ADDED:
* envs.GetEnvErr(), envs.GetEnvErrNoBlank(), envs.EnvErrNoVal
  This allows error-returned env vars for nonexistent/empty values.

envs/types.go

@@ -0,0 +1,20 @@
+package envs
+
+type (
+	/*
+		EnvErrNoVal is an error containing the variable that does not exist
+		(and information surrounding the errored state).
+	*/
+	EnvErrNoVal struct {
+		// VarName is the variable name/key name originally specified in the function call.
+		VarName             string `json:"var" toml:"VariableName" yaml:"Variable Name/Key" xml:"key,attr"`
+		// WasFound is only used for GetEnvErrNoBlank(). It is true if the variable was found/populated.
+		WasFound            bool   `json:"found" toml:"Found" yaml:"Found" xml:"found,attr"`
+		// WasRequiredNonEmpty indicates that this error was returned in a context where a variable was required to be non-empty (e.g. via GetEnvErrNoBlank()) but was empty.
+		WasRequiredNonEmpty bool   `json:"reqd_non_empty" toml:"RequiredNonEmpty" yaml:"Required Non-Empty" xml:"reqNonEmpty,attr"`
+		// IgnoreWhitespace is true if the value was found but its evaluation was done against a whitestripped version.
+		IgnoreWhitespace    bool   `json:"ignore_ws" toml:"IgnoreWhitespace" yaml:"Ignore Whitespace" xml:"ignoreWhitespace,attr"`
+		// WasWhitespace is true if the value was whitespace-only.
+		WasWhitespace       bool   `json:"was_ws" toml:"WasWhitespace" yaml:"Was Whitespace Only" xml:"wasWhitespace,attr"`
+	}
+)