assertThrows | /assert/mod.ts | std@0.223.0

function assertThrows

import { assertThrows } from "https://dotland.deno.dev/std@0.223.0/assert/mod.ts";

assertThrows(fn: () => unknown, msg?: string): unknown

Executes a function, expecting it to throw. If it does not, then it throws.

assertThrows<E extends Error = Error>(

fn: () => unknown,

ErrorClass: new (...args: any[]) => E,

msgIncludes?: string,

msg?: string,

): E

Executes a function, expecting it to throw. If it does not, then it throws. An error class and a string that should be included in the error message can also be asserted.

Executes a function, expecting it to throw. If it does not, then it throws.

To assert that an asynchronous function rejects, use assertRejects.

Examples

Example 1

import { assertThrows } from "https://deno.land/std@0.223.0/assert/assert_throws.ts";

assertThrows(() => { throw new TypeError("hello world!"); }); // Doesn't throw
assertThrows(() => console.log("hello world!")); // Throws

Parameters

fn: () => unknown

optional

msg: string

Returns

unknown

Executes a function, expecting it to throw. If it does not, then it throws. An error class and a string that should be included in the error message can also be asserted.

To assert that an asynchronous function rejects, use assertRejects.

Examples

Example 1

import { assertThrows } from "https://deno.land/std@0.223.0/assert/assert_throws.ts";

assertThrows(() => { throw new TypeError("hello world!"); }, TypeError); // Doesn't throw
assertThrows(() => { throw new TypeError("hello world!"); }, RangeError); // Throws

Type Parameters

optional

E extends Error = Error

Parameters

fn: () => unknown

ErrorClass: new (...args: any[]) => E

optional

msgIncludes: string

optional

msg: string