TypeScriptTips

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Narrow types

@RiccardoOdone•Suggest a tip•

Avoid casting, especially to any.

const element = document.querySelector('#id')

(element as any).style.display = 'block'
// ⛔️ element could be null

const element = document.querySelector('#id')

if (element instanceof HTMLElement) {
  element.style.display = 'block'
}
Type-safe carouselDo not throwFilter using a type assertionUse precise typesType-safe string templatingEnumerating a union typeNumbers with unitsZero nullEnumerating statusesAnd typesAvoiding window as anyUse descriptive valuesCheck authorization with typesExtract union types from record typesKeep in sync with conditional typesType-safe pickPass arguments by namePick instead of duplicatingPrevent mutationsType aliasesModel with different typesPrefer static types over testsPush conditionals downType-level functionsCheck Authorization With Types (again)From Union to TupleLimit typesLaser-focused typesCallable typesPartial considered harmfulSatisfy typesWTH?!Parse, don't castNarrow typesFetch footgunModel with different types (2)Polymorphic typesParse, don't cast (again)Type-safe envObject vs Recordconst Type ParametersDigType checksExpand intellisenseNumbers with units (2)Unchecked indexed accessExtract instead of duplicating

TypeScriptTips

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