throw2
v1.0.1
Published
Sugar syntax to throw exceptions as an expression.
Downloads
24
Maintainers
Readme
This is a fork of anton-rudeshko/node-throw. If you are familiar with the original project, see Fork Changes below.
throw2
You can't use throw
statement in expressions in JavaScript:
arg = arg || throw new Error('arg is required');
// ^^^^^
// Uncaught SyntaxError: Unexpected token 'throw'
This tiny library is wrapping throw
in a function:
// Use capital T to distinguish this module from the throw keyword
const Throw = require('throw2');
// ...
arg = arg || Throw('arg is required');
This is particularly useful when using nullish coalescing operator and optional chaining operator:
value = obj?.nested?.value ?? Throw('value not found');
Installation
npm i throw2
Require/Import
CommonJS:
const Throw = require('throw2');
ESM:
import Throw from 'throw2';
More Usage Options
You can compose dynamic error messages by providing multiple arguments:
typeof arg === 'string' || Throw('Invalid arg. Received:', arg, 'Should be string.');
You can also use your own error types:
/*...expression...*/ || Throw(new MyCustomError(arg1, arg2));
// Or
/*...expression...*/ || Throw(MyCustomError, arg1, arg2); // Creates a MyCustomError with arg1 and arg2
Note
Throw as an expression is currently a Stage 2 TC39 proposal, so this package might no longer be necessary in the future.
Fork Changes
The main difference is that node-throw
uses Node.js API,
so it doesn't work in the browser without a polyfill.
throw2
works in any CommonJS environment. (e.g. noje.js and webpack)
Also, printf
-like message formatting is not supported by throw2
. Use template literals instead; or pass multiple arguments to the function. (see usage examples)
License
MIT (see LICENSE.md)