@xylabs/assert

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Base functionality used throughout XY Labs TypeScript/JavaScript libraries

Reference

@xylabs/assert

Functions

- assertDefinedEx
- assertEx

$3

### assertDefinedEx

@xylabs/assert

Implementation of assertDefinedEx that handles all overloads.

Call Signature

``ts function assertDefinedEx(expr, messageFunc?): T;`

Asserts that a value is defined (not undefined) and returns the value. Throws an error if the value is undefined.

`$3`

The type of value to check

`$3`

Expression to be evaluated for being defined

undefined | T

`$3`

AssertExMessageFunc\<T\>

Function that returns a message for the error if expression is undefined

`$3`

The value of the expression (guaranteed to be defined)

`$3`

Error with the message returned by messageFunc

`$3`

`typescript // Simple usage with a message function const value = assertDefinedEx(possiblyUndefined, () => 'Value must be defined')

// Using with type narrowing const config: Config | undefined = loadConfig() const safeConfig = assertDefinedEx(config, () => 'Config failed to load') // safeConfig is now type Config (not Config | undefined)`

`Call Signature`

`ts function assertDefinedEx(expr, errorFunc?): T;`

Asserts that a value is defined (not undefined) and returns the value. Throws a custom error if the value is undefined.

`$3`

The type of value to check

`$3`

R extends Error

The type of error to throw

`$3`

Expression to be evaluated for being defined

undefined | T

`$3`

AssertExErrorFunc\<T, R\>

Function that returns a custom error instance if expression is undefined

`$3`

The value of the expression (guaranteed to be defined)

`$3`

Custom error returned by errorFunc

`$3`

`typescript // Using with a custom error const user = assertDefinedEx(getUser(), () => new UserNotFoundError('User not found'))`

`Call Signature`

`ts function assertDefinedEx(expr): T;`

Asserts that a value is defined (not undefined) and returns the value. Throws an error if the value is undefined.

`$3`

The type of value to check

`$3`

Expression to be evaluated for being defined

undefined | T

`$3`

The value of the expression (guaranteed to be defined)

`$3`

Use overload with message function instead - passing a message will soon be required

`$3`

Error with a generic message

`Call Signature`

`ts function assertDefinedEx(expr, message?): T;`

Asserts that a value is defined (not undefined) and returns the value. Throws an error with the provided message if the value is undefined.

`$3`

The type of value to check

`$3`

Expression to be evaluated for being defined

undefined | T

`$3`

string

Error message if expression is undefined

`$3`

The value of the expression (guaranteed to be defined)

`$3`

Replace string with () => string for consistency

`$3`

Error with the provided message

### assertEx

@xylabs/assert

*

Implementation of assertEx that handles all overloads.

`Call Signature`

`ts function assertEx(expr, messageFunc?): T;`

Asserts that an expression is truthy and returns the value. Throws an error if the expression is falsy.

`$3`

The type of value to check

`$3`

Expression to be evaluated for truthiness

undefined | null | T

`$3`

AssertExMessageFunc\<T\>

Function that returns a message for the error if expression is falsy

`$3`

The value of the expression (guaranteed to be truthy)

`$3`

Error with the message returned by messageFunc

`$3`

`typescript // Simple usage with a message function const value = assertEx(possiblyFalsy, () => 'Value must be truthy')

// Using with type narrowing const config: Config | null = loadConfig() const safeConfig = assertEx(config, () => 'Config failed to load') // safeConfig is now type Config (not Config | null)`

`Call Signature`

`ts function assertEx(expr, errorFunc?): T;`

Asserts that an expression is truthy and returns the value. Throws a custom error if the expression is falsy.

`$3`

The type of value to check

`$3`

R extends Error

The type of error to throw

`$3`

Expression to be evaluated for truthiness

undefined | null | T

`$3`

AssertExErrorFunc\<T, R\>

Function that returns a custom error instance if expression is falsy

`$3`

The value of the expression (guaranteed to be truthy)

`$3`

Custom error returned by errorFunc

`$3`

`typescript // Using with a custom error const user = assertEx(getUser(), () => new UserNotFoundError('User not found'))`

`Call Signature`

`ts function assertEx(expr): T;`

Asserts that an expression is truthy and returns the value. Throws an error if the expression is falsy.

`$3`

The type of value to check

`$3`

Expression to be evaluated for truthiness

undefined | null | T

`$3`

The value of the expression (guaranteed to be truthy)

`$3`

Use overload with message function instead - passing a message will soon be required

`$3`

Error with a generic message

`Call Signature`

`ts function assertEx(expr, message?): T;`

Asserts that an expression is truthy and returns the value. Throws an error with the provided message if the expression is falsy.

`$3`

The type of value to check

`$3`

Expression to be evaluated for truthiness

undefined | null | T

`$3`

string

Error message if expression is falsy

`$3`

The value of the expression (guaranteed to be truthy)

$3

Replace string with () => string for consistency

$3

Error with the provided message

Part of sdk-js

Maintainers

- Arie Trouw (arietrouw.com)
- Matt Jones
- Joel Carter
- Jordan Trouw

License

> See the LICENSE file for license details

Credits

Made with 🔥 and ❄️ by XYLabs

[logo]: https://cdn.xy.company/img/brand/XYPersistentCompany_Logo_Icon_Colored.svg

[main-build]: https://github.com/xylabs/sdk-js/actions/workflows/build.yml/badge.svg
[main-build-link]: https://github.com/xylabs/sdk-js/actions/workflows/build.yml
[npm-badge]: https://img.shields.io/npm/v/@xylabs/assert.svg
[npm-link]: https://www.npmjs.com/package/@xylabs/assert
[codacy-badge]: https://app.codacy.com/project/badge/Grade/c8e15e14f37741c18cfb47ac7245c698
[codacy-link]: https://www.codacy.com/gh/xylabs/sdk-js/dashboard?utm_source=github.com&utm_medium=referral&utm_content=xylabs/sdk-js&utm_campaign=Badge_Grade
[codeclimate-badge]: https://api.codeclimate.com/v1/badges/c5eb068f806f0b047ea7/maintainability
[codeclimate-link]: https://codeclimate.com/github/xylabs/sdk-js/maintainability
[snyk-badge]: https://snyk.io/test/github/xylabs/sdk-js/badge.svg?targetFile=package.json
[snyk-link]: https://snyk.io/test/github/xylabs/sdk-js?targetFile=package.json

[npm-downloads-badge]: https://img.shields.io/npm/dw/@xylabs/assert
[npm-license-badge]: https://img.shields.io/npm/l/@xylabs/assert

[jsdelivr-badge]: https://data.jsdelivr.com/v1/package/npm/@xylabs/assert/badge
[jsdelivr-link]: https://www.jsdelivr.com/package/npm/@xylabs/assert

[socket-badge]: https://socket.dev/api/badge/npm/package/@xylabs/assert
[socket-link]: https://socket.dev/npm/package/@xylabs/assert

@xylabs/assert

[![logo][]](https://xylabs.com)

Base functionality used throughout XY Labs TypeScript/JavaScript libraries

Reference

@xylabs/assert

Functions

- assertDefinedEx
- assertEx

$3

### assertDefinedEx

@xylabs/assert

Implementation of assertDefinedEx that handles all overloads.

Call Signature

``ts function assertDefinedEx(expr, messageFunc?): T;`

Asserts that a value is defined (not undefined) and returns the value. Throws an error if the value is undefined.

`$3`

The type of value to check

`$3`

Expression to be evaluated for being defined

undefined | T

`$3`

AssertExMessageFunc\<T\>

Function that returns a message for the error if expression is undefined

`$3`

The value of the expression (guaranteed to be defined)

`$3`

Error with the message returned by messageFunc

`$3`

`typescript // Simple usage with a message function const value = assertDefinedEx(possiblyUndefined, () => 'Value must be defined')

`Call Signature`

`ts function assertDefinedEx(expr, errorFunc?): T;`

Asserts that a value is defined (not undefined) and returns the value. Throws a custom error if the value is undefined.

`$3`

The type of value to check

`$3`

R extends Error

The type of error to throw

`$3`

Expression to be evaluated for being defined

undefined | T

`$3`

AssertExErrorFunc\<T, R\>

Function that returns a custom error instance if expression is undefined

`$3`

The value of the expression (guaranteed to be defined)

`$3`

Custom error returned by errorFunc

`$3`

`typescript // Using with a custom error const user = assertDefinedEx(getUser(), () => new UserNotFoundError('User not found'))`

`Call Signature`

`ts function assertDefinedEx(expr): T;`

Asserts that a value is defined (not undefined) and returns the value. Throws an error if the value is undefined.

`$3`

The type of value to check

`$3`

Expression to be evaluated for being defined

undefined | T

`$3`

The value of the expression (guaranteed to be defined)

`$3`

Use overload with message function instead - passing a message will soon be required

`$3`

Error with a generic message

`Call Signature`

`ts function assertDefinedEx(expr, message?): T;`

Asserts that a value is defined (not undefined) and returns the value. Throws an error with the provided message if the value is undefined.

`$3`

The type of value to check

`$3`

Expression to be evaluated for being defined

undefined | T

`$3`

string

Error message if expression is undefined

`$3`

The value of the expression (guaranteed to be defined)

`$3`

Replace string with () => string for consistency

`$3`

Error with the provided message

### assertEx

@xylabs/assert

*

Implementation of assertEx that handles all overloads.

`Call Signature`

`ts function assertEx(expr, messageFunc?): T;`

Asserts that an expression is truthy and returns the value. Throws an error if the expression is falsy.

`$3`

The type of value to check

`$3`

Expression to be evaluated for truthiness

undefined | null | T

`$3`

AssertExMessageFunc\<T\>

Function that returns a message for the error if expression is falsy

`$3`

The value of the expression (guaranteed to be truthy)

`$3`

Error with the message returned by messageFunc

`$3`

`typescript // Simple usage with a message function const value = assertEx(possiblyFalsy, () => 'Value must be truthy')

// Using with type narrowing const config: Config | null = loadConfig() const safeConfig = assertEx(config, () => 'Config failed to load') // safeConfig is now type Config (not Config | null)`

`Call Signature`

`ts function assertEx(expr, errorFunc?): T;`

Asserts that an expression is truthy and returns the value. Throws a custom error if the expression is falsy.

`$3`

The type of value to check

`$3`

R extends Error

The type of error to throw

`$3`

Expression to be evaluated for truthiness

undefined | null | T

`$3`

AssertExErrorFunc\<T, R\>

Function that returns a custom error instance if expression is falsy

`$3`

The value of the expression (guaranteed to be truthy)

`$3`

Custom error returned by errorFunc

`$3`

`typescript // Using with a custom error const user = assertEx(getUser(), () => new UserNotFoundError('User not found'))`

`Call Signature`

`ts function assertEx(expr): T;`

Asserts that an expression is truthy and returns the value. Throws an error if the expression is falsy.

`$3`

The type of value to check

`$3`

Expression to be evaluated for truthiness

undefined | null | T

`$3`

The value of the expression (guaranteed to be truthy)

`$3`

Use overload with message function instead - passing a message will soon be required

`$3`

Error with a generic message

`Call Signature`

`ts function assertEx(expr, message?): T;`

Asserts that an expression is truthy and returns the value. Throws an error with the provided message if the expression is falsy.

`$3`

The type of value to check

`$3`

Expression to be evaluated for truthiness

undefined | null | T

`$3`

string

Error message if expression is falsy

`$3`

The value of the expression (guaranteed to be truthy)

$3

Replace string with () => string for consistency

$3

Error with the provided message

Part of sdk-js

Maintainers

- Arie Trouw (arietrouw.com)
- Matt Jones
- Joel Carter
- Jordan Trouw

License

> See the LICENSE file for license details

Credits

Made with 🔥 and ❄️ by XYLabs

[logo]: https://cdn.xy.company/img/brand/XYPersistentCompany_Logo_Icon_Colored.svg

[npm-downloads-badge]: https://img.shields.io/npm/dw/@xylabs/assert
[npm-license-badge]: https://img.shields.io/npm/l/@xylabs/assert

[jsdelivr-badge]: https://data.jsdelivr.com/v1/package/npm/@xylabs/assert/badge
[jsdelivr-link]: https://www.jsdelivr.com/package/npm/@xylabs/assert

[socket-badge]: https://socket.dev/api/badge/npm/package/@xylabs/assert
[socket-link]: https://socket.dev/npm/package/@xylabs/assert