@polkadot/util
Version:
A collection of useful utilities for @polkadot
45 lines (44 loc) • 1.44 kB
JavaScript
Object.defineProperty(exports, "__esModule", { value: true });
exports.assert = assert;
exports.assertReturn = assertReturn;
exports.assertUnreachable = assertUnreachable;
const function_js_1 = require("./is/function.js");
/**
* @name assert
* @summary Checks for a valid test, if not Error is thrown.
* @description
* Checks that `test` is a truthy value. If value is falsy (`null`, `undefined`, `false`, ...), it throws an Error with the supplied `message`. When `test` passes, `true` is returned.
* @example
* <BR>
*
* ```javascript
* const { assert } from '@polkadot/util';
*
* assert(true, 'True should be true'); // passes
* assert(false, 'False should not be true'); // Error thrown
* assert(false, () => 'message'); // Error with 'message'
* ```
*/
function assert(condition, message) {
if (!condition) {
throw new Error((0, function_js_1.isFunction)(message)
? message()
: message);
}
}
/**
* @name assertReturn
* @description Returns when the value is not undefined/null, otherwise throws assertion error
*/
function assertReturn(value, message) {
assert(value !== undefined && value !== null, message);
return value;
}
/**
* @name assertUnreachable
* @description An assertion helper that ensures all codepaths are followed
*/
function assertUnreachable(x) {
throw new Error(`This codepath should be unreachable. Unhandled input: ${x}`);
}
;