Feature Checker Service Reference

Service Overview

The Feature Checker service evaluates feature values at runtime. Every method enforces the hierarchy:

subscription override → plan value → feature default

The service answers questions at both subscription and customer levels, exposes plan-access helpers, and can summarize usage patterns. Results draw from FeatureValueResolver, so the hierarchy is consistent everywhere.

Accessing the Service

import { Subscrio } from 'core.typescript';

const subscrio = new Subscrio({ database: { connectionString: process.env.DATABASE_URL! } });
const featureChecker = subscrio.featureChecker;

using Subscrio.Core;

var subscrio = new Subscrio(config);
var featureChecker = subscrio.FeatureChecker;

Method Catalog

Method Reference

getValueForSubscription

Description

Resolves a feature value for a single subscription using override → plan value → feature default precedence.

getValueForSubscription<T = string>(
  subscriptionKey: string,
  featureKey: string,
  defaultValue?: T
): Promise<T | null>

const seats = await featureChecker.getValueForSubscription<number>(
  'sub_1001',
  'seat-limit',
  0
);

Task<T?> GetValueForSubscriptionAsync<T>(
    string subscriptionKey,
    string featureKey,
    T? defaultValue = default
)

var seats = await subscrio.FeatureChecker.GetValueForSubscriptionAsync<string>(
    "sub_1001",
    "seat-limit",
    "0"
);

Expected Results

• Loads subscription, plan, and feature.
• Applies resolver hierarchy; if any entity is missing returns fallback rather than throwing.

Potential Errors

• None.

isEnabledForSubscription

Description

Convenience helper for toggle features at the subscription level.

isEnabledForSubscription(subscriptionKey: string, featureKey: string): Promise<boolean>

const hasBranding = await featureChecker.isEnabledForSubscription(
  'sub_enterprise',
  'custom-branding'
);

Task<bool> IsEnabledForSubscriptionAsync(string subscriptionKey, string featureKey)

var hasBranding = await subscrio.FeatureChecker.IsEnabledForSubscriptionAsync(
    "sub_enterprise",
    "custom-branding"
);

Expected Results

• Wraps getValueForSubscription and checks for 'true'.

Potential Errors

• None.

getAllFeaturesForSubscription

Description

Resolves every feature for the subscription's product, returning a map of featureKey → value.

getAllFeaturesForSubscription(subscriptionKey: string): Promise<Map<string, string>>

const resolved = await featureChecker.getAllFeaturesForSubscription('sub_1001');
console.log(resolved.get('max-projects'));

Task<Dictionary<string, string>> GetAllFeaturesForSubscriptionAsync(string subscriptionKey)

var resolved = await subscrio.FeatureChecker.GetAllFeaturesForSubscriptionAsync("sub_1001");
Console.WriteLine(resolved.GetValueOrDefault("max-projects"));

Expected Results

• Loads subscription, plan, and product, then queries all product features.
• Resolves each feature via the hierarchy and populates the map.
• Returns empty map when the plan cannot be resolved.

Potential Errors

getValueForCustomer

Description

Resolves a feature for a customer/product pair by scanning active/trial subscriptions (up to MAX_SUBSCRIPTIONS_PER_CUSTOMER).

getValueForCustomer<T = string>(
  customerKey: string,
  productKey: string,
  featureKey: string,
  defaultValue?: T
): Promise<T | null>

const maxProjects = await featureChecker.getValueForCustomer<number>(
  'acme-corp',
  'projecthub',
  'max-projects',
  0
);

Task<T?> GetValueForCustomerAsync<T>(
    string customerKey,
    string productKey,
    string featureKey,
    T? defaultValue = default
)

var maxProjects = await subscrio.FeatureChecker.GetValueForCustomerAsync<string>(
    "acme-corp",
    "projecthub",
    "max-projects",
    "0"
);

Expected Results

• Loads customer, product, and feature; returns fallback when any missing.
• Fetches subscriptions for the customer, filters to active/trial entries for the product.
• Applies resolver across subscriptions, honoring override precedence if multiple subscriptions exist.

Potential Errors

• None.

isEnabledForCustomer

Description

Boolean helper that wraps getValueForCustomer.

isEnabledForCustomer(
  customerKey: string,
  productKey: string,
  featureKey: string
): Promise<boolean>

const hasApiAccess = await featureChecker.isEnabledForCustomer(
  'acme-corp',
  'projecthub',
  'api-access'
);

Task<bool> IsEnabledForCustomerAsync(
    string customerKey,
    string productKey,
    string featureKey
)

var hasApiAccess = await subscrio.FeatureChecker.IsEnabledForCustomerAsync(
    "acme-corp",
    "projecthub",
    "api-access"
);

Expected Results

• Wraps getValueForCustomer and checks for 'true'.

Potential Errors

• None.

getAllFeaturesForCustomer

Description

Aggregates every feature value for a customer/product pair by considering all active/trial subscriptions.

getAllFeaturesForCustomer(
  customerKey: string,
  productKey: string
): Promise<Map<string, string>>

const customerFeatures = await featureChecker.getAllFeaturesForCustomer(
  'acme-corp',
  'projecthub'
);

Task<Dictionary<string, string>> GetAllFeaturesForCustomerAsync(
    string customerKey,
    string productKey
)

var customerFeatures = await subscrio.FeatureChecker.GetAllFeaturesForCustomerAsync(
    "acme-corp",
    "projecthub"
);

Expected Results

• Loads customer/product; returns empty map when either missing.
• Resolves all product features using the resolver across relevant subscriptions.

Potential Errors

• None.

hasPlanAccess

Description

Checks whether a customer currently holds an active or trial subscription for a given plan.

hasPlanAccess(
  customerKey: string,
  productKey: string,
  planKey: string
): Promise<boolean>

const hasPro = await featureChecker.hasPlanAccess('acme-corp', 'projecthub', 'professional');

Task<bool> HasPlanAccessAsync(
    string customerKey,
    string productKey,
    string planKey
)

var hasPro = await subscrio.FeatureChecker.HasPlanAccessAsync("acme-corp", "projecthub", "professional");

Expected Results

• Validates all entities exist.
• Loads subscriptions for the customer and searches for an active/trial entry referencing the plan.

Potential Errors

• None.

getActivePlans

Description

Lists plan keys for every active/trial subscription held by a customer (across all products).

getActivePlans(customerKey: string): Promise<string[]>

const plans = await featureChecker.getActivePlans('acme-corp');

Task<List<string>> GetActivePlansAsync(string customerKey)

var plans = await subscrio.FeatureChecker.GetActivePlansAsync("acme-corp");

Expected Results

• Loads customer and their subscriptions.
• Batch-fetches plans to avoid N+1 queries and returns plan keys.

Potential Errors

• None.

getFeatureUsageSummary

Description

Produces a usage rollup showing how features resolve (enabled/disabled/numeric/text) for a customer/product pair and includes the customer's subscription count.

getFeatureUsageSummary(
  customerKey: string,
  productKey: string
): Promise<{
  activeSubscriptions: number;
  enabledFeatures: string[];
  disabledFeatures: string[];
  numericFeatures: Map<string, number>;
  textFeatures: Map<string, string>;
}>

const summary = await featureChecker.getFeatureUsageSummary('acme-corp', 'projecthub');
console.log(summary.enabledFeatures);

Task<FeatureUsageSummaryDto> GetFeatureUsageSummaryAsync(
    string customerKey,
    string productKey
)

var summary = await subscrio.FeatureChecker.GetFeatureUsageSummaryAsync("acme-corp", "projecthub");
Console.WriteLine(string.Join(", ", summary.EnabledFeatures));

Expected Results

• Counts the customer's subscriptions (regardless of product filter).
• Resolves all product features (using defaults when customer/product missing) and classifies values by FeatureDto.valueType.

Potential Errors

• None.

Related Workflows

• Products must associate features and plans must set feature values for meaningful results; otherwise values fall back to feature defaults.
• Subscription-level overrides come from SubscriptionManagementService.addFeatureOverride.
• Cache high-traffic queries such as getAllFeaturesForCustomer to avoid recalculating the same maps repeatedly.