promise-dedup/lib/index.js

Deduplicate any promise

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.dedup = exports.cache = void 0;
var fast_json_stable_stringify_1 = __importDefault(require("fast-json-stable-stringify"));
exports.cache = new Map();
function dedup(exec, key, stale) {
    if (stale === void 0) { stale = "settled"; }
    var strKey = (0, fast_json_stable_stringify_1.default)(key);
    var cached = exports.cache.get(strKey);
    if (cached)
        return cached;
    var promise = exec();
    exports.cache.set(strKey, promise);
    var clean = function () {
        exports.cache.delete(strKey);
    };
    if (typeof stale === "number") {
        setTimeout(clean, stale);
    }
    else if (stale === "settled") {
        promise = promise.then(function (value) {
            clean();
            return value;
        }, function (error) {
            clean();
            throw error;
        });
    }
    return promise;
}
exports.dedup = dedup;