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x/scaffold/src/deps/npm.ts>assertError

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function assertError
import { assertError } from "https://deno.land/x/scaffold@0.3.0/src/deps/npm.ts";

Assert that the given value is an Error.

If the value is not an Error, a helpful TypeError will be thrown.

This can be useful as any value could potentially be thrown, but in practice, it's always an Error. However, because of this, TypeScript makes the caught error in a try/catch statement unknown, which is inconvenient to deal with.

Examples

Example 1

import {assertError} from 'ts-extras';

try {
    fetchUnicorns();
} catch (error: unknown) {
    assertError(error)

    // `error` is now of type `Error`

    if (error.message === 'Failed to fetch') {
        retry();
        returnl
    }

    throw error;
}

Parameters

value: unknown

Returns

asserts value is Error