Assert
Helper functions that have to do with asserting.
Functions
assertDefined()
function assertDefined<T>(value, ...__namedParameters): asserts value is Exclude<T, undefined>
Defined in: functions/assert.ts:27
Helper function to throw an error if the provided value is equal to undefined.
This is useful to have TypeScript narrow a T | undefined value to T in a concise way.
Type Parameters
| Type Parameter |
|---|
T |
Parameters
| Parameter | Type |
|---|---|
value | T |
...__namedParameters | [undefined] extends [T] ? [string] : ["The assertion is useless because the provided value does not contain undefined."] |
Returns
asserts value is Exclude<T, undefined>
assertNotNull()
function assertNotNull<T>(value, ...__namedParameters): asserts value is Exclude<T, null>
Defined in: functions/assert.ts:45
Helper function to throw an error if the provided value is equal to null.
This is useful to have TypeScript narrow a T | null value to T in a concise way.
Type Parameters
| Type Parameter |
|---|
T |
Parameters
| Parameter | Type |
|---|---|
value | T |
...__namedParameters | [null] extends [T] ? [string] : ["The assertion is useless because the provided value does not contain null."] |
Returns
asserts value is Exclude<T, null>
assertObject()
function assertObject(value, msg): asserts value is Record<string, unknown>
Defined in: functions/assert.ts:67
Helper function to throw an error if the provided value is not an object (i.e. a TypeScript record).
This is useful to have TypeScript narrow a Record<string, unknown> | undefined value to
Record<string, unknown> in a concise way.
Under the hood, this function uses the isObject helper function.
Parameters
| Parameter | Type |
|---|---|
value | unknown |
msg | string |
Returns
asserts value is Record<string, unknown>
assertType()
function assertType(
value,
type,
msg): asserts value is unknown
Defined in: functions/assert.ts:77
Helper function to throw an error if the provided value is not of the provided type.
Parameters
| Parameter | Type |
|---|---|
value | unknown |
type | | "string" | "number" | "boolean" | "undefined" | "object" | "function" | "array" | "null" |
msg | string |
Returns
asserts value is unknown