ts-custom-matcher

customMatcherHelper.ts

export {};

declare global {
  // eslint-disable-next-line @typescript-eslint/no-namespace
  namespace jest {
    interface Matchers<R> {
      toBeMemberOfEnum(): R;
    }
  }
}

expect.extend({
  toBeMemberOfEnum(received, enumeration) {
    const enumValues = Object.keys(enumeration).map(k => enumeration[k])
    const pass = enumValues.find(received)
    if (pass) {
      return {
        message: () =>
          `expected ${received} not to be member of enum ${enumeration}.
           ${enumeration} values: ${enumValues}
          `,
        pass: true,
      };
    } else {
      return {
        message: () =>
        `expected ${received} to be member of enum ${enumeration}.
        ${enumeration} values: ${enumValues}
        `,
        pass: false,
      };
    }
  },
})