Type Alias IsSymbolLiteral<T>

IsSymbolLiteral: LiteralCheck<T, symbol>

Returns a boolean for whether the given type is a symbol literal type.

Useful for: - providing strongly-typed functions when given literal arguments - type utilities, such as when constructing parsers and ASTs

Type Parameters

  • T

Example

import type {IsSymbolLiteral} from 'type-fest';

type Get<Obj extends Record<symbol, number>, Key extends keyof Obj> =
	IsSymbolLiteral<Key> extends true
		? Obj[Key]
		: number;

function get<Obj extends Record<symbol, number>, Key extends keyof Obj>(o: Obj, key: Key) {
	return o[key] as Get<Obj, Key>;
}

const symbolLiteral = Symbol('literal');
const symbolValue: symbol = Symbol('value');

get({[symbolLiteral]: 1} as const, symbolLiteral);
//=> 1

get({[symbolValue]: 1} as const, symbolValue);
//=> number

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