refactor application.yaml to become an os definition #40

src/application/Common/Enum.ts

@@ -0,0 +1,43 @@
+// Because we cannot do "T extends enum" 😞 https://github.com/microsoft/TypeScript/issues/30611
+type EnumType = number | string;
+type EnumVariable<T extends EnumType, TEnumValue extends EnumType> = { [key in T]: TEnumValue };
+
+export interface IEnumParser<TEnum> {
+    parseEnum(value: string, propertyName: string): TEnum;
+}
+export function createEnumParser<T extends EnumType, TEnumValue extends EnumType>(
+    enumVariable: EnumVariable<T, TEnumValue>): IEnumParser<TEnumValue> {
+    return {
+        parseEnum: (value, propertyName) => parseEnumValue(value, propertyName, enumVariable),
+    };
+}
+function parseEnumValue<T extends EnumType, TEnumValue extends EnumType>(
+    value: string,
+    enumName: string,
+    enumVariable: EnumVariable<T, TEnumValue>): TEnumValue {
+    if (!value) {
+        throw new Error(`undefined ${enumName}`);
+    }
+    if (typeof value !== 'string') {
+        throw new Error(`unexpected type of ${enumName}: "${typeof value}"`);
+    }
+    const casedValue = getEnumNames(enumVariable)
+        .find((enumValue) => enumValue.toLowerCase() === value.toLowerCase());
+    if (!casedValue) {
+        throw new Error(`unknown ${enumName}: "${value}"`);
+    }
+    return enumVariable[casedValue as keyof typeof enumVariable];
+}
+
+export function getEnumNames<T extends EnumType, TEnumValue extends EnumType>(
+    enumVariable: EnumVariable<T, TEnumValue>): string[] {
+    return Object
+        .values(enumVariable)
+        .filter((enumMember) => typeof enumMember === 'string') as string[];
+}
+
+export function getEnumValues<T extends EnumType, TEnumValue extends EnumType>(
+    enumVariable: EnumVariable<T, TEnumValue>): TEnumValue[] {
+    return getEnumNames(enumVariable)
+        .map((level) => enumVariable[level]) as TEnumValue[];
+}