Entries if you want to just access the type of the array of entries (which is the return of the .entries() method).
import type {Entry} from 'type-fest';
interface Example {
someKey: number;
}
const manipulatesEntry = (example: Entry<Example>) => [
// Does some arbitrary processing on the key (with type information available)
example[0].toUpperCase(),
// Does some arbitrary processing on the value (with type information available)
example[1].toFixed(),
];
const example: Example = {someKey: 1};
const entry = Object.entries(example)[0] as Entry<Example>;
const output = manipulatesEntry(entry);
// Objects
const objectExample = {a: 1};
const objectEntry: Entry<typeof objectExample> = ['a', 1];
// Arrays
const arrayExample = ['a', 1];
const arrayEntryString: Entry<typeof arrayExample> = [0, 'a'];
const arrayEntryNumber: Entry<typeof arrayExample> = [1, 1];
// Maps
const mapExample = new Map([['a', 1]]);
const mapEntry: Entry<typeof mapExample> = ['a', 1];
// Sets
const setExample = new Set(['a', 1]);
const setEntryString: Entry<typeof setExample> = ['a', 'a'];
const setEntryNumber: Entry<typeof setExample> = [1, 1];
Many collections have an
entriesmethod which returns an array of a given object's own enumerable string-keyed property [key, value] pairs. TheEntrytype will return the type of that collection's entry.For example the https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries|
Object, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/entries|Map, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/entries|Array, and https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/entries|Setcollections all have this method. Note thatWeakMapandWeakSetdo not have this method since their entries are not enumerable.