Guards the value to be a symbol.

const guardSymbol = <Payload extends object>(
  value: symbol,
  callback?: ResultCallback<symbol, Payload>,
  payload?: Payload
): value is symbol => isSymbol(value, callback, payload);

Generic type variables


The Payload generic type variable constrained by object indicates the type of optional parameter payload of the supplied callback function and payload optional parameter of the guardSymbol() function from which it captures its value.


value: symbol

A symbol type value to guard.

callback?: ResultCallback<null, Payload>

The optional callback function of ResultCallback type with parameters, the value that has been checked, the result of this check, and payload of generic type variable Payload with optional properties from the provided payload, to handle them before the result return. By default, it uses resultCallback() function.

payload?: Payload

An optional object of the generic type variable Payload is assigned to the payload of the given callback function.

Return type

value issymbol

The return type is a boolean as the result of its statement indicating the value is a symbol.


The return value is a boolean indicating whether the value is a symbol.

Example usage

// Example usage.
import { guardSymbol } from '@angular-package/type';

const SYMBOL_NUMBER: unique symbol = Symbol(27);
const SYMBOL_STRING: unique symbol = Symbol('Twenty seven');

guardSymbol(SYMBOL_NUMBER); // true; return type `value is symbol`
guardSymbol(SYMBOL_STRING); // true; return type `value is symbol`

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