@reliance/feature-flags/test/setFeature.test.js

A package for determining feature flag status based on environment variables or flag objects.

const {
  PredicateNotAFunctionError,
  InvalidFeatureDefinition,
} = require("../src/error");
const { setFeature, features } = require("../src/setFeature");

describe("setFeature", () => {
  test("should add valid feature predicates to the features object", () => {
    const localFeatures = {
      newUI: (params) => params.isBetaUser === true,
      adminDashboard: (params) => params.admin === true,
    };
    setFeature(localFeatures);
    expect(features.newUI).toBeDefined();
    expect(features.adminDashboard).toBeDefined();
    expect(features.newUI({ isBetaUser: true })).toBe(true);
    expect(features.adminDashboard({ admin: true })).toBe(true);
  });

  test("should throw error if feature Definitions is not an object", () => {
    expect(() => {
      setFeature(null);
    }).toThrow("Feature definitions must be an object and cannot be null");

    expect(() => {
      setFeature("invalid");
    }).toThrow("Feature definitions must be an object and cannot be null");
  });

  test("should throw PredicateNotAFunctionError if a feature value is not a function", () => {
    const invalidFeatures = {
      validFeature: () => true,
      invalidFeature: "not-a-function",
    };

    expect(() => {
      setFeature(invalidFeatures);
    }).toThrow(PredicateNotAFunctionError);
  });

  test("should throw InvalidFeatureDefinition if not a valid feature object", () => {
    const invalideFeature = "hello";

    expect(() => {
      setFeature(invalideFeature);
    }).toThrow(InvalidFeatureDefinition);
  });
});