serverless-spy
Version:
CDK-based library for writing elegant integration tests on AWS serverless architecture and an additional web console to monitor events in real time.
46 lines (45 loc) • 1.2 kB
JavaScript
export const memoize = (provider, isExpired, requiresRefresh) => {
let resolved;
let pending;
let hasResult;
let isConstant = false;
const coalesceProvider = async () => {
if (!pending) {
pending = provider();
}
try {
resolved = await pending;
hasResult = true;
isConstant = false;
}
finally {
pending = undefined;
}
return resolved;
};
if (isExpired === undefined) {
return async (options) => {
if (!hasResult || options?.forceRefresh) {
resolved = await coalesceProvider();
}
return resolved;
};
}
return async (options) => {
if (!hasResult || options?.forceRefresh) {
resolved = await coalesceProvider();
}
if (isConstant) {
return resolved;
}
if (requiresRefresh && !requiresRefresh(resolved)) {
isConstant = true;
return resolved;
}
if (isExpired(resolved)) {
await coalesceProvider();
return resolved;
}
return resolved;
};
};