@midwayjs/cache-manager
Version:
midway cache manager
78 lines • 2.05 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.coalesceAsync = void 0;
const callbacks = new Map();
/**
* Enqueue a promise for the group identified by `key`.
*
* All requests received for the same key while a request for that key
* is already being executed will wait. Once the running request settles
* then all the waiting requests in the group will settle, too.
* This minimizes how many times the function itself runs at the same time.
* This function resolves or rejects according to the given function argument.
*/
async function coalesceAsync(
/**
* Any identifier to group requests together.
*/
key,
/**
* The function to run.
*/
fn) {
if (!hasKey(key)) {
addKey(key);
try {
const result = await Promise.resolve(fn());
coalesce({ key, result });
return result;
}
catch (error) {
coalesce({ key, error });
throw error;
}
}
return enqueue(key);
}
exports.coalesceAsync = coalesceAsync;
function hasKey(key) {
return callbacks.has(key);
}
function addKey(key) {
callbacks.set(key, []);
}
function removeKey(key) {
callbacks.delete(key);
}
function addCallbackToKey(key, callback) {
const stash = getCallbacksByKey(key);
stash.push(callback);
callbacks.set(key, stash);
}
function getCallbacksByKey(key) {
var _a;
return (_a = callbacks.get(key)) !== null && _a !== void 0 ? _a : [];
}
function enqueue(key) {
return new Promise((resolve, reject) => {
const callback = { resolve, reject };
addCallbackToKey(key, callback);
});
}
function dequeue(key) {
const stash = getCallbacksByKey(key);
removeKey(key);
return stash;
}
function coalesce(options) {
const { key, error, result } = options;
dequeue(key).forEach(callback => {
if (error) {
callback.reject(error);
}
else {
callback.resolve(result);
}
});
}
//# sourceMappingURL=prmoiseCoalesce.js.map