isx

TypeScript-first validate collections for JavaScript data.

What

This is a very small collection of validate functions. The validate function provides a custom type guard whenever it can.

Naming rule

The validate function is provided according to the following naming conventions

monadic - isX

isString

Whether the value is string or not.

import { isString } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isString("hello world"), true);
assertEquals(isString(1000), false);

isNumber

Whether the value is number or not.

import { isNumber } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isNumber(1000), true);
assertEquals(isNumber("hello world"), false);

isBigint

Whether the value is bigint or not.

import { isBigint } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isBigint(1000n), true);
assertEquals(isBigint(undefined), false);

isNull

Whether the value is null or not.

import { isNull } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isNull(null), true);
assertEquals(isNull(undefined), false);

isUndefined

Whether the value is undefined or not.

import { isUndefined } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isUndefined(undefined), true);
assertEquals(isUndefined(null), false);

isBoolean

Whether the value is boolean or not.

import { isBoolean } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isBoolean(true), true);
assertEquals(isBoolean(null), false);

isFunction

Whether the value is Function or not.

import { isFunction } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isFunction(() => {}), true);
assertEquals(isFunction({}), false);

isObject

Whether the value is object or not.

import { isObject } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isObject({}), true);
assertEquals(isObject(null), false);

isSymbol

Whether the value is symbol or not.

import { isSymbol } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isSymbol(Symbol("symbol")), true);
assertEquals(isSymbol(null), false);

isTruthy

Whether the value is TruthyLike or not.

import { isTruthy } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isTruthy(1), true);
assertEquals(isTruthy("a"), true);
assertEquals(isTruthy(0), false);

Currently, there is no way to represent a type other than a specific subset from a type with an infinite subset, such as string or number.

type TruthyLike =
  | Exclude<string, "">
  | Exclude<number, 0 | -0>
  | Exclude<bigint, 0n>
  | Exclude<boolean, false>
  | symbol
  | object;

isFalsy

Whether the value is FalsyLike or not.

import { isFalsy } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isFalsy(0), true);
assertEquals(isFalsy(""), true);
assertEquals(isFalsy("a"), false);

NaN is not a Unit type, but a number.

type FalsyLike =
  | typeof NaN
  | 0
  | -0
  | 0n
  | ""
  | null
  | undefined
  | false;

isTrue

Whether the value is true or not.

import { isTrue } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isTrue(true), true);
assertEquals(isTrue(false), false);

isFalse

Whether the value is false or not.

import { isFalse } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isFalse(false), true);
assertEquals(isFalse(true), false);

isPrimitive

Whether the value is Primitive or not.

import { isPrimitive } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isPrimitive(true), true);
assertEquals(isPrimitive(() => {}), false);

type Primitive =
  | number
  | string
  | boolean
  | bigint
  | undefined
  | null
  | symbol;

isPromise

Whether the value is Promise or not.

import { isPromise } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isPromise(Promise.resolve()), true);
assertEquals(isPromise({}), false);

isDate

Whether the value is Date or not.

import { isDate } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isDate(new Date()), true);
assertEquals(isDate({}), false);

isError

Whether the value is Error or not.

import { isError } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isError(Error()), true);
assertEquals(isError(new SyntaxError()), true);
assertEquals(isError(new Date()), false);

isIterable

Whether the value is Iterable or not.

import { isIterable } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isIterable(""), true);
assertEquals(isIterable({}), false);

isAsyncIterable

Whether the value is AsyncIterable or not

import { isAsyncIterable } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(
  isAsyncIterable({
    async *[Symbol.asyncIterator]() {
      yield "hello";
    },
  }),
  true,
);
assertEquals(isAsyncIterable(() => {}), false);

String subsets

Validates a subset of string. All validate functions must satisfy ⊂ string.

isHexColorFormat

Whether the value is Hex color or not.

import { isHexColorFormat } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isHexColorFormat("#000000"), true);
assertEquals(isHexColorFormat("#FFF"), true);
assertEquals(isHexColorFormat("#ggg"), false);

isHostnameFormat

Whether the value is hostname format or not.

import { isHostnameFormat } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isHostnameFormat("a"), true);
assertEquals(isHostnameFormat("test.test"), true);
assertEquals(isHostnameFormat("."), false);

isRfc3339DateFormat

Whether the value is RFC 3339 date format or not.

The format compliant with RFC 3339, 5.6. Internet Date/Time Format, full-date

import { isRfc3339DateFormat } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isRfc3339DateFormat("0000-01-01"), true);
assertEquals(isRfc3339DateFormat("0000-00-00"), false);

isRfc3339TimeFormat

Whether the value is RFC 3339 time format or not.

The format compliant with RFC 3339, 5.6. Internet Date/Time Format, full-time

import { isRfc3339TimeFormat } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isRfc3339TimeFormat("00:00:00+00:00"), true);
assertEquals(isRfc3339TimeFormat("23:59:59Z"), true);
assertEquals(isRfc3339TimeFormat("24:00:00Z"), false);

isRfc3339DateTimeFormat

Whether the value is RFC 3339 date time format or not.

The format compliant with RFC 3339, 5.6. Internet Date/Time Format, date-time

import { isRfc3339DateTimeFormat } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isRfc3339DateTimeFormat("0001-01-01T00:00:00Z"), true);
assertEquals(isRfc3339DateTimeFormat("9999-12-31T23:59:59+19:59"), true);
assertEquals(isRfc3339DateTimeFormat("0000-00-00T00:00:00Z"), false);

Number subsets

Validates a subset of number. All validate functions must satisfy ⊂ number.

isOdd

Whether the value is odd or not.

import { isOdd } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isOdd(1), true);
assertEquals(isOdd(0), false);

isEven

Whether the value is even or not.

import { isEven } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isEven(0), true);
assertEquals(isEven(1), false);

isPositiveNumber

Whether the value is positive number or not.

import { isPositiveNumber } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isPositiveNumber(1), true);
assertEquals(isPositiveNumber(0), false);

isNegativeNumber

Whether the value is negative number or not.

import { isNegativeNumber } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isNegativeNumber(-1), true);
assertEquals(isNegativeNumber(0), false);

isNonNegativeInteger

Whether the value is non negative integer or not.

import { isNonNegativeInteger } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isNonNegativeInteger(0), true);
assertEquals(isNonNegativeInteger(1.0), true);
assertEquals(isNonNegativeInteger(-1), false);

Object subsets

Validates a subset of object. All validate functions must satisfy ⊂ object.

hasOwn

Whether the value own the property or not. The difference from Object.hasOwn is that it has a Type guard.

import { hasOwn } from "https://deno.land/x/isx@$VERSION/mod.ts";

const object: object = {};
if (hasOwn("", object)) {
  object[""]; // No type error.
}

Date subsets

Validates a subset of Date. All validate functions must satisfy ⊂ Date.

isValidDate

Whether the value is valid Date or not.

import { isValidDate } from "https://deno.land/x/isx@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";
assertEquals(isValidDate(new Date("2000/1/1")), true);
assertEquals(isValidDate(new Date("invalid")), false);

License

Released under the MIT license