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export type User = ReturnType<typeof verifyUser>;
// ^ Type defined for 'free'
// + Pro: Less wasted effort aligning types AND validation.
// + Pro: More 'honest', not obscured by layers, `any` or `as`
// - Con: Easy to accidentally change a public interface.
// (Prefer explicit definitions at your library/module boundaries.)
export function verifyUser(data: { [key: string]: unknown; }) {
if (!data || typeof data !== 'object')
throw new Error(`User must be a valid object.`);
@justsml
justsml / aws-client-options.js
Last active April 20, 2023 01:22
Using LocalStack with AWS SDK v3 - determine options for AWS client constructors.
const DEFAULT_LOCALSTACK_EDGE_PORT = 4566;
/**
* Get options for use in AWS client constructors.
*
* Configure the `AWS_ENDPOINT` environment variable to set an endpoint.
*
* ### Example
*
* To run tests w/ LocalStack: `AWS_ENDPOINT=http://127.0.0.1:4566 jest`
/**
* A **Smarter** retry wrapper with currying!
*/
function retryCurry(fn, retriesLeft = 5) {
const retryFn = (...args) => fn(...args)
.catch(err => retriesLeft > 0
? retryFn(fn, retriesLeft - 1)
: Promise.reject(err)
})
return retryFn
const checkForRedirect = (response) => {
// Check for temporary redirect (307), or permanent (308)
if (response.status === 307 || response.status === 308) {
const location = response.headers.get('location')
if (!location) {
return Promise.reject(new Error('Invalid HTTP Redirect! No Location header.'));
}
// You can change the behavior here to any custom logic:
// e.g. open a "confirm" modal, log the redirect url, etc.
return fetch(location)
@justsml
justsml / extensions.json
Last active November 22, 2022 18:57
VS Code Config
{
// See https://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
// Extension identifier format: ${publisher}.${name}. Example: vscode.csharp
// List of extensions which should be recommended for users of this workspace.
"recommendations": [
"streetsidesoftware.code-spell-checker",
"kisstkondoros.vscode-codemetrics",
"ms-azuretools.vscode-docker",
"dbaeumer.vscode-eslint",
/**
* `filteredFlagFactory` supports 3 states of a feature flag:
* - True,
* - False,
* - and restricted by ID(s).
*
*/
export function filteredFlagFactory(
flagValue: string,
defaultIdField = 'userId'
@justsml
justsml / asyncIterable-stream-forAwaitOf-examples.ts
Created August 1, 2022 00:24
Examples of using for-await-of syntax to consume streams.
export const batchStream = (size: number) =>
async function* batchStream<TStreamType>(stream: AsyncIterable<TStreamType>) {
let buffer: TStreamType[] = [];
for await (const chunk of stream) {
buffer.push(chunk);
if (buffer.length >= size) {
yield buffer;
buffer = [];
}
}
@justsml
justsml / addSignalListener.mjs
Last active August 18, 2022 04:04
Nodejs snippet to handle `process` events (OS signals) easily with `addSignalListener()`
/**
* Handle process signal events easily with `addSignalListener()`.
*
* Automatically returns a convenient method to unregister your event handler(s), in case you need that functionality.
*
* ## Examples
*
* ```js
* addSignalListener(['SIGINT', 'SIGHUP', 'SIGUSR2'], (signal, event) =>
* console.log(`Process received a signal! ${signal}`, { event });
@justsml
justsml / settings.json
Created June 21, 2022 00:50
VS Code Recommended Settings
{
// TypeScript configuration
// Use the project-local typescript version / may be desired, comment out on old TS versions
"typescript.tsdk": "node_modules/typescript/lib",
"typescript.preferences.importModuleSpecifier": "relative",
// Terminal settings
"terminal.integrated.scrollback": 100000, // Terminal scrollback line limit
// Set terminal font size to match VS Code font size. See: https://www.NerdFonts.com/
"terminal.integrated.fontFamily": "'MesloLGS NF', 'Hack Nerd Font', Menlo, Monaco, 'Courier New', monospace",

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