Straightforward, zero-dependencies and powerful utility to check types, instances or values. Takes away the dirt, lets you write more solid code and drastically improves code readability.
npm install powercheck --save
import is, { Throw as check } from 'powercheck';
is('foo', String);
// -> true
is('foo', Number);
// -> false
check('foo', String);
// -> undefined
check('foo', Number);
// throws an exceptionis('foo', is.optional(String));
// -> true
is('bar', is.optional(is.equals('bar')));
// -> trueOr: import "optional" using ES6 modules
import is, { optional } from 'powercheck';
is('foo', optional(String));
// -> trueis(new Date(), Date);
// -> true
is(new SomeConstructor(), SomeConstructor);
// -> trueis('foo', is.equals('bar'));
// -> falseis('foo', is.oneOf([Number, Boolean]));
// -> false
is('foo', is.oneOf([is.equals(2), String]));
// -> true
is('foo', is.oneOf([
is.equals('foo'),
is.equals('bar')
]));
// -> true
is('foo', is.oneOf(['foo', 'bar'].map(is.equals)));
// -> trueis('foo', is.every([String, is.equals('foo')]));
// -> true
is(123, is.every([Number, is.validate(n => n < 100)]));
// -> falseN.B.: validations will be executed in order. When a validation fails, remaining validations won't be executed. So, in is.validate() functions (custom validations), you can rely on the previous validations.
is('foo', is.validate((value) => {
return ['foo', 'bar'].indexOf(value) > -1;
}));
// -> trueimport { isEmail } from 'validator';
is('[email protected]', is.validate(isEmail));
// -> trueis(['foo', 'bar'], [String]);
// -> true
is(['foo', 400], [String]);
// -> falseN.B.: it's recursive
is([['foo', 'test'], ['bar']], [[String]]);
// -> trueis({
foo: 'bar'
}, {
foo: String
});
// -> true
is({
foo: 'bar',
baz: 'kopz'
}, {
foo: String,
baz: Number
});
// -> falseN.B.: extra properies won't be accepted
is({
foo: 'bar',
baz: 'kopz',
extra: 'boo'
}, {
foo: String,
baz: String
});
// -> false
N.B.: mising properies won't be accepted
is({
foo: 'bar',
baz: 'kopz',
}, {
foo: String,
baz: String,
extra: String
});
// -> falseimport is, { Throw as check } from 'powercheck';
is('foo', Number);
// -> false (boolean)
check('foo', Number);
// -> throws an exception
check('foo', Number, new Error('Failed'));
// -> throws a custom error
check('foo', Number, (value, error) => {
return new Error('Type ' + error.got + ' is invalid. Should be ' + error.expectedType + '.');
});
// -> throws a custom error with extra information
check('foo', String);
// -> undefined (no exception has been thrown, nothing is being returned either)
check(undefined, is.optional(Number));
// -> undefined (no exception has been thrown, nothing is being returned either)is() returns a boolean and check() throws an exception.
| Key | Value |
|---|---|
| value | Anything you want to check the type, instance and/or value for |
| validator | String, Number, Object, Array, Function, Symbol (ES6), SomeConstructor, is.optional(<validator>), is.validate((value) => trueOrFalse), is.equals(compareValue), is.oneOf([validators]), [<validator>], {key1: <validator>, ...} |
If you have questions, you can ask them on StackOverflow mentioning me @jessedvrs.
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