@philiprehberger/guard
v0.1.5221 downloadsMIT
Runtime type guard utilities with TypeScript narrowing
$
npm install @philiprehberger/guardREADME
@philiprehberger/guard
Runtime type guard utilities with TypeScript narrowing
Installation
npm install @philiprehberger/guard
Usage
import { isString, isNumber, isArrayOf, isObjectWith, assert } from '@philiprehberger/guard';
if (isString(val)) {
val.toUpperCase(); // narrowed to string
}
const isUser = isObjectWith({
name: isString,
age: isNumber,
});
if (isUser(data)) {
data.name; // typed as string
data.age; // typed as number
}
assert(input, isArrayOf(isString)); // throws or narrows to string[]
Composing Guards
import { isOneOf, isString, isNumber, isTupleOf } from '@philiprehberger/guard';
const isStringOrNumber = isOneOf(isString, isNumber);
const isPair = isTupleOf(isString, isNumber);
isStringOrNumber('hello'); // true
isPair(['hello', 42]); // true
API
| Function | Description |
|---|---|
isString, isNumber, isBoolean, isNull, isUndefined, isNil, isBigInt, isSymbol | Primitive guards |
isArray, isObject, isPlainObject, isMap, isSet, isDate, isRegExp, isError, isPromise, isFunction | Structural guards |
isNonEmpty, isPositive, isNegative, isInteger, isFiniteNumber, isNonNullish | Value guards |
isOneOf(...guards) | Union of guards |
isArrayOf(guard) | Array where all items match guard |
isObjectWith(shape) | Object matching shape of guards |
isTupleOf(...guards) | Tuple matching guards positionally |
assert(value, guard, message?) | Throw if guard fails, narrow otherwise |
Development
npm install
npm run build
npm test
Support
If you find this project useful: