nest-feature-guard/dist/feature-guard.js

A powerful, NestJS-first feature flag guard and decorator library with Redis caching support. Perfect for implementing feature toggles, A/B testing, gradual rollouts, and user-specific feature access control.

"use strict";
var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
    return c > 3 && r && Object.defineProperty(target, key, r), r;
};
var __metadata = (this && this.__metadata) || function (k, v) {
    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
};
var __param = (this && this.__param) || function (paramIndex, decorator) {
    return function (target, key) { decorator(target, key, paramIndex); }
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.FeatureGuard = void 0;
exports.FeatureFlag = FeatureFlag;
const common_1 = require("@nestjs/common");
const core_1 = require("@nestjs/core");
const feature_flag_constants_1 = require("./feature-flag.constants");
let FeatureGuard = class FeatureGuard {
    store;
    reflector;
    constructor(store, reflector) {
        this.store = store;
        this.reflector = reflector;
    }
    async canActivate(context) {
        const request = context.switchToHttp().getRequest();
        const userId = request.__user_id;
        const isAdmin = request.__is_admin;
        if (userId === undefined && isAdmin !== true) {
            return false;
        }
        if (isAdmin === true) {
            return true;
        }
        const flags = this.reflector.get(feature_flag_constants_1.FEATURE_FLAG_KEY, context.getHandler());
        const options = this.reflector.get(feature_flag_constants_1.FEATURE_FLAG_OPTIONS_KEY, context.getHandler());
        if (flags === undefined || flags.length === 0)
            return false;
        const featureFlags = await Promise.all(flags.map(async (flag) => {
            const feature = await this.store.getFeature(flag);
            const hasFlag = userId !== undefined ? await this.store.hasFeatureFlag(flag, userId) : false;
            return { flag, feature, hasFlag };
        }));
        request.__feature_flags = {
            ...request.__feature_flags,
            ...featureFlags.reduce((acc, { flag, feature, hasFlag }) => {
                acc[flag] = feature?.enabled === true && hasFlag;
                return acc;
            }, {}),
        };
        if (options?.scope !== feature_flag_constants_1.FeatureFlagScope.SERVICE) {
            if (featureFlags.some(({ feature, hasFlag }) => !feature?.enabled || !hasFlag)) {
                return false;
            }
        }
        return true;
    }
    static isFeatureEnabled(request, flag) {
        return request.__feature_flags?.[flag] === true;
    }
};
exports.FeatureGuard = FeatureGuard;
exports.FeatureGuard = FeatureGuard = __decorate([
    (0, common_1.Injectable)(),
    __param(0, (0, common_1.Inject)(feature_flag_constants_1.FEATURE_GUARD_STORE)),
    __param(1, (0, common_1.Inject)(feature_flag_constants_1.FEATURE_GUARD_REFLECTOR)),
    __metadata("design:paramtypes", [Object, core_1.Reflector])
], FeatureGuard);
function FeatureFlag(flags, options) {
    const flagArray = Array.isArray(flags) ? flags : [flags];
    return (0, common_1.applyDecorators)((0, common_1.SetMetadata)(feature_flag_constants_1.FEATURE_FLAG_KEY, flagArray), (0, common_1.SetMetadata)(feature_flag_constants_1.FEATURE_FLAG_OPTIONS_KEY, options), (0, common_1.UseGuards)(FeatureGuard));
}
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