Check if a value meets criteria
npm install @rnacanvas/value-checkWith npm:
``
npm install @rnacanvas/value-check
All exports of this package can be accessed as named imports.
`typescript`
// some example imports
import { isNumber, isString } from '@rnacanvas/value-check';
import { isNullish } from '@rnacanvas/value-check';
import { isFiniteNumber, isPositiveFiniteNumber } from '@rnacanvas/value-check';
import type { NonNullObject } from '@rnacanvas/value-check';
Returns true if and only if a value is of type number.
`javascript
isNumber(5); // true
isNumber(Infinity); // true
isNumber(NaN); // true
isNumber('5'); // false
isNumber({}); // false
isNumber(null); // false
`
Returns true if and only if a value is of type number
and it is not , Infinity or -Infinity.
`javascript
isFiniteNumber(6); // true
isFiniteNumber(0); // true
isFiniteNumber(-3.27); // true
isFiniteNumber(NaN); // false
isFiniteNumber(Infinity); // false
isFiniteNumber(-Infinity); // false
isFiniteNumber('5'); // false
isFiniteNumber({}); // false
isFiniteNumber(null); // false
`
Returns true if and only if a value is NaN, Infinity or -Infinity.
`javascript
isNonFiniteNumber(NaN); // true
isNonFiniteNumber(Infinity); // true
isNonFiniteNumber(-Infinity); // true
isNonFiniteNumber(6); // false
isNonFiniteNumber(0); // false
isNonFiniteNumber(-3.27); // false
isNoNFiniteNumber('5'); // false
isNoNFiniteNumber({}); // false
isNoNFiniteNumber(null); // false
`
Returns true if and only a value is of type number
and is finite and positive.
`javascript
isPositiveFiniteNumber(6); // true
isPositiveFiniteNumber(0); // false
isPositiveFiniteNumber(-3.27); // false
isPositiveFiniteNumber(NaN); // false
isPositiveFiniteNumber(Infinity); // false
isPositiveFiniteNumber(-Infinity); // false
isPositiveFiniteNumber('5'); // false
isPositiveFiniteNumber({}); // false
isPositiveFiniteNumber(null); // false
`
Returns true if and only a value is of type number
and is finite and nonnegative.
`javascript
isNonNegativeFiniteNumber(6); // true
isNonNegativeFiniteNumber(0); // true
isNonNegativeFiniteNumber(-3.27); // false
isNonNegativeFiniteNumber(NaN); // false
isNonNegativeFiniteNumber(Infinity); // false
isNonNegativeFiniteNumber(-Infinity); // false
isNonNegativeFiniteNumber('5'); // false
isNonNegativeFiniteNumber({}); // false
isNonNegativeFiniteNumber(null); // false
`
Returns true if and only if a value is of type string.
`javascript
isString(''); // true
isString('string'); // true
isString(5); // false
isString({}); // false
isString(null); // false
`
The Nullish type includes the values null and undefined.
`typescript`
type Nullish = null | undefined;
Returns true if and only if a value is null or undefined.
`javascript
isNullish(null); // true
isNullish(undefined); // true
isNullish(1); // false
isNullish('a'); // false
isNullish({}); // false
`
The NonNullObject type matches values of type object that are not null.
`typescript`
type NonNullObject = { [name: string]: unknown };
Returns true if and only if a value is of type object and is not null.
`javascript
isNonNullObject({}); // true
isNonNullObject({ 'a': 2, 'b': 3 }); // true
isNonNullObject(null); // false
isNonNullObject(5); // false
isNonNullObject('asdf'); // false
`
Returns true if and only if a value is an array.
`javascript
isArray([]); // true
isArray([1, '2', 'a', {}]); // true
isArray({}); // false
isArray(2); // false
isArray(null); // false
`
Returns true if and only if a value is an empty array
(i.e., an array with zero items in it).
`javascript
isEmptyArray([]); // true
isEmptyArray([1, 'b', 3]); // false
// not an array
isEmptyArray('[]'); // false
`
Returns true if and only if a value is a nonempty array
(i.e., an array with at least one item).
`javascript
isNonEmptyArray([1, 'b', 3]); // true
isNonEmptyArray(['a']); // true
isNonEmptyArray([]); // false
// not an array
isNonEmptyArray('[1, 2, 3]'); // false
`
Returns true if and only if a value is an array of numbers.
Vacuously returns true for an empty array.
`javascript
isNumbersArray([]); // true
isNumbersArray([2]); // true
isNumbersArray([-1, -2, -3, -4]); // true
// nonfinite numbers
isNumbersArray([NaN, Infinity, -Infinity]); // true
isNumbersArray(2); // false
isNumbersArray(['2']); // false
isNumbersArray([1, 2, 3, '4', 5]); // false
`
Returns true if and only if a value is an array of numbers and is nonempty.
`javascript
isNonEmptyNumbersArray([1]); // true
isNonEmptyNumbersArray([1, 2, 3, 4]); // true
isNonEmptyNumbersArray([]); // false
// nonfinite numbers
isNonEmptyNumbersArray([NaN, Infinity, -Infinity]); // true
// not an array of numbers
isNonEmptyNumbersArray([1, '2', 3]); // false
// not an array (is a string)
isNonEmptyNumbersArray('[1, 2, 3]'); // false
`
Returns true if and only if a value is an array of finite numbers.
Vacuously returns true for an empty array.
`javascript
isFiniteNumbersArray([10]); // true
isFiniteNumbersArray([-1, 5.5, 2, 101.308]); // true
isFiniteNumbersArray([]); // true
isFiniteNumbersArray([NaN, Infinity, -Infinity]); // false
isFiniteNumbersArray(10); // false
isFiniteNumbersArray([1, '2', 3]); // false
`
Returns true if and only if a value is an array of nonfinite numbers.
Vacuously returns true for an empty array.
`javascript
isNonFiniteNumbersArray([NaN, Infinity, -Infinity]); // true
isNonFiniteNumbersArray([]); // true
isNonFiniteNumbersArray([1, 2, 3, 4]); // false
isNonFiniteNumbersArray([NaN, NaN, 3, NaN]); // false
// not an array
isNonFiniteNumbersArray(Infinity); // false
`
Returns true if and only if a value is an array of strings.
Vacuously returns true for an empty array.
`javascript
isStringsArray(['asdf']); // true
isStringsArray(['', ' ', 'A', '4']); // true
isStringsArray([]); // true
isStringsArray(['1', '2', 3, '4']); // false
// not an array
isStringsArray('asdf'); // false
`
Returns true if and only if a value is an array of strings and is nonempty.
`javascript
isNonEmptyStringsArray(['asdf']); // true
isNonEmptyStringsArray(['a', 'b', 'c', 'd']); // true
isNonEmptyStringsArray([]); // false
// not an array of strings
isNonEmptyStringsArray(['a', 'b', 3, 'd']); // false
// not an array
isNonEmptyStringsArray('asdf'); // false
``