nmalyschkin/helperJS

Aggregation of useful JS functions

functions

makeThrottled

Higher order function to throttle function calls. Returns void since throttled execution is asyncronuous. If the return value is needed, wrap inside a Promise and make a side-effect to resolve the promise.

retrieveFromIterator

Generic function to retrieve X elements from an iterator or iteratable. Useful for infinite generators or lazy chunking.

exist

Checks for null and undefined – can be used instead of nullish coalescing.

makeMemoized

Higher order function to memoize pure functions. Shallow compares args for that purpose.

makeCached

Higher order function to cache pure functions with a single argument.

types

StrictUnion

The typescript discriminated union checks the last object as valid, while with StrictUnion it get's invalid.

interface B {
  a: true;
  b: number;
}
interface C {
  a?: false;
  c: number;
}
type Union = StrictUnion<B | C>;

const valid1: Union = {
  a: false,
  c: 5,
};
const valid2: Union = {
  c: 4,
};
const valid3: Union = {
  a: true,
  b: 4,
};
const invalid: Union = {
  b: 4,
  c: 4,
};