@launchdarkly/js-server-sdk-common/dist/hooks/HookRunner.js

LaunchDarkly Server SDK for JavaScript - common code

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const BEFORE_EVALUATION_STAGE_NAME = 'beforeEvaluation';
const AFTER_EVALUATION_STAGE_NAME = 'afterEvaluation';
const UNKNOWN_HOOK_NAME = 'unknown hook';
class HookRunner {
    constructor(_logger, hooks) {
        this._logger = _logger;
        this._hooks = [];
        this._hooks.push(...hooks);
    }
    async withEvaluationSeries(key, context, defaultValue, methodName, method) {
        // This early return is here to avoid the extra async/await associated with
        // using withHooksDataWithDetail.
        if (this._hooks.length === 0) {
            return method();
        }
        return this.withEvaluationSeriesExtraDetail(key, context, defaultValue, methodName, async () => {
            const detail = await method();
            return { detail };
        }).then(({ detail }) => detail);
    }
    /**
     * This function allows extra information to be returned with the detail for situations like
     * migrations where a tracker is returned with the detail.
     */
    async withEvaluationSeriesExtraDetail(key, context, defaultValue, methodName, method) {
        if (this._hooks.length === 0) {
            return method();
        }
        const { hooks, hookContext } = this._prepareHooks(key, context, defaultValue, methodName);
        const hookData = this._executeBeforeEvaluation(hooks, hookContext);
        const result = await method();
        this._executeAfterEvaluation(hooks, hookContext, hookData, result.detail);
        return result;
    }
    _tryExecuteStage(method, hookName, stage) {
        var _a;
        try {
            return stage();
        }
        catch (err) {
            (_a = this._logger) === null || _a === void 0 ? void 0 : _a.error(`An error was encountered in "${method}" of the "${hookName}" hook: ${err}`);
            return {};
        }
    }
    _hookName(hook) {
        var _a, _b;
        try {
            return (_a = hook === null || hook === void 0 ? void 0 : hook.getMetadata().name) !== null && _a !== void 0 ? _a : UNKNOWN_HOOK_NAME;
        }
        catch (_c) {
            (_b = this._logger) === null || _b === void 0 ? void 0 : _b.error(`Exception thrown getting metadata for hook. Unable to get hook name.`);
            return UNKNOWN_HOOK_NAME;
        }
    }
    _executeAfterEvaluation(hooks, hookContext, updatedData, result) {
        var _a;
        // This iterates in reverse, versus reversing a shallow copy of the hooks,
        // for efficiency.
        for (let hookIndex = hooks.length - 1; hookIndex >= 0; hookIndex -= 1) {
            const hook = hooks[hookIndex];
            const data = (_a = updatedData[hookIndex]) !== null && _a !== void 0 ? _a : {};
            this._tryExecuteStage(AFTER_EVALUATION_STAGE_NAME, this._hookName(hook), () => { var _a, _b; return (_b = (_a = hook === null || hook === void 0 ? void 0 : hook.afterEvaluation) === null || _a === void 0 ? void 0 : _a.call(hook, hookContext, data, result)) !== null && _b !== void 0 ? _b : {}; });
        }
    }
    _executeBeforeEvaluation(hooks, hookContext) {
        return hooks.map((hook) => this._tryExecuteStage(BEFORE_EVALUATION_STAGE_NAME, this._hookName(hook), () => { var _a, _b; return (_b = (_a = hook === null || hook === void 0 ? void 0 : hook.beforeEvaluation) === null || _a === void 0 ? void 0 : _a.call(hook, hookContext, {})) !== null && _b !== void 0 ? _b : {}; }));
    }
    _prepareHooks(key, context, defaultValue, methodName) {
        // Copy the hooks to use a consistent set during evaluation. Hooks could be added and we want
        // to ensure all correct stages for any give hook execute. Not for instance the afterEvaluation
        // stage without beforeEvaluation having been called on that hook.
        const hooks = [...this._hooks];
        const hookContext = {
            flagKey: key,
            context,
            defaultValue,
            method: methodName,
        };
        return { hooks, hookContext };
    }
    addHook(hook) {
        this._hooks.push(hook);
    }
}
exports.default = HookRunner;
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