★ guardTrue()


Guards the value to be true.

const guardTrue = <Payload extends object>(
  value: true,
  callback?: ResultCallback<true, Payload>,
  payload?: Payload
): value is true => isTrue(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 guardTrue() function from which it captures its value.


value: true

The value of true type 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 istrue

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


The return value is a boolean indicating whether the value is a boolean type or an instance of Boolean equal to true.

Example usage

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

const valTrue = true as any;
const valFalse = false;

guardTrue(valTrue); // false, value is false
guardTrue(valFalse); // true, value is false
guardTrue(new Boolean(valTrue) as any); // false, value is false
guardTrue(new Boolean(valFalse) as any); // true, value is false

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