feat(node-config-provider): add utility booleanSelector

packages/node-config-provider/src/booleanSelector.spec.ts

@@ -0,0 +1,31 @@
+import { booleanSelector, SelectorType } from "./booleanSelector";
+
+describe(booleanSelector.name, () => {
+  const key = "key";
+  const obj: { [key]: any } = {} as any;
+
+  describe.each(Object.entries(SelectorType))(`Selector %s`, (selectorKey, selectorValue) => {
+    beforeEach(() => {
+      delete obj[key];
+    });
+
+    it(`should return undefined if ${key} is not defined`, () => {
+      expect(booleanSelector(obj, key, SelectorType[selectorKey])).toBeUndefined();
+    });
+
+    it.each([
+      [true, "true"],
+      [false, "false"],
+    ])(`should return boolean %s if ${key}="%s"`, (output, input) => {
+      obj[key] = input;
+      expect(booleanSelector(obj, key, SelectorType[selectorKey])).toBe(output);
+    });
+
+    it.each(["0", "1", "yes", "no", undefined, null, void 0, ""])(`should throw if ${key}=%s`, (input) => {
+      obj[key] = input;
+      expect(() => booleanSelector(obj, key, SelectorType[selectorKey])).toThrow(
+        `Cannot load ${selectorValue} "${key}". Expected "true" or "false", got ${obj[key]}.`
+      );
+    });
+  });
+});

packages/node-config-provider/src/booleanSelector.ts

@@ -0,0 +1,19 @@
+export enum SelectorType {
+  ENV = "env",
+  CONFIG = "shared config entry",
+}
+
+/**
+ * Returns boolean value true/false for string value "true"/"false",
+ * if the string is defined in obj[key]
+ * Returns undefined, if obj[key] is not defined.
+ * Throws error for all other cases.
+ *
+ * @internal
+ */
+export const booleanSelector = (obj: { [key: string]: string }, key: string, type: SelectorType) => {
+  if (!(key in obj)) return undefined;
+  if (obj[key] === "true") return true;
+  if (obj[key] === "false") return false;
+  throw new Error(`Cannot load ${type} "${key}". Expected "true" or "false", got ${obj[key]}.`);
+};

packages/node-config-provider/src/index.ts

@@ -1 +1,2 @@
+export * from "./booleanSelector";
 export * from "./configLoader";