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Collection of validation functions for JavaScript data.

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

Module structure and capability

Module can be divided into two categories.

Top-type module

Top-type module can accept any JavaScript data. In other words, it accepts the unknown type, which is top-type.

Most of them can be used to identify the type by a type guard.

The module directly under namespace is it.

Sub-type module

Sub-type modules are modules that perform type-dependent operations. It can use type-specific methods and compare values.

For example, the module under number is a sub-type module that takes a number type as an argument.

isString

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Whether the input is string or not.

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

isNumber

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Whether the input is number or not.

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

isBigint

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Whether the input is bigint or not.

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

isNull

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Whether the input is null or not.

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

isUndefined

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Whether the input is undefined or not.

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

isBoolean

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Whether the input is boolean or not.

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

isFunction

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Whether the input is Function or not.

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

isObject

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Whether the input is object or not.

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

isSymbol

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Whether the input is symbol or not.

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

isNullable

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Whether the input is null or undefined or not.

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

isPrimitive

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Whether the input is Primitive or not.

import { isPrimitive } from "https://deno.land/x/isx@$VERSION/is_primitive.ts";
import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
assertEquals(isPrimitive(true), true);
assertEquals(isPrimitive(() => {}), false);
type Primitive =
  | number
  | string
  | boolean
  | bigint
  | undefined
  | null
  | symbol;

isArray

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Whether the input is array or not.

Use only if input contains ReadOnlyArray. It improves type inference. Otherwise, use Array.isArray.

This exists only because of TypeScript bug #17002. When this is fixed, this function will no longer be provided.

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

isPromise

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Whether the input is Promise or not.

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

isDate

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Whether the input is Date or not.

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

isError

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Whether the input is Error or not.

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

isNonNullable

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Whether the input is NonNullable or not.

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

isRegExp

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Whether the input is RegExp of not.

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

Numeric subtypes

Validates a subtype of number or bigint.

isPositiveNumber

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Whether the input is positive number or not.

import { isPositiveNumber } from "https://deno.land/x/isx@$VERSION/numeric/is_positive_number.ts";
import { assert, assertFalse } from "https://deno.land/std/testing/asserts.ts";
assert(isPositiveNumber(1));
assert(isPositiveNumber(Infinity));
assertFalse(isPositiveNumber(0));

isNonPositiveNumber

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Whether the input is non-positive number or not. Non-positive number means less than or equal to zero.

import { isNonPositiveNumber } from "https://deno.land/x/isx@$VERSION/numeric/is_non_positive_number.ts";
import { assert, assertFalse } from "https://deno.land/std/testing/asserts.ts";
assert(isNonPositiveNumber(0));
assert(isNonPositiveNumber(-1));
assertFalse(isNonPositiveNumber(1));

isNegativeNumber

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Whether the input is negative number or not.

import { isNegativeNumber } from "https://deno.land/x/isx@$VERSION/numeric/is_negative_number.ts";
import { assert, assertFalse } from "https://deno.land/std/testing/asserts.ts";
assert(isNegativeNumber(-1));
assertFalse(isNegativeNumber(0));

isNonNegativeNumber

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Whether the input is non-negative number or not. Non-negative number means greater than or equal to zero.

import { isNonNegativeNumber } from "https://deno.land/x/isx@$VERSION/numeric/is_non_negative_number.ts";
import { assert, assertFalse } from "https://deno.land/std/testing/asserts.ts";
assert(isNonNegativeNumber(0));
assert(isNonNegativeNumber(1));
assertFalse(isNonNegativeNumber(-1));

isUnitInterval

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Whether the input is unit interval or not. The unit interval refers to the interval between 0 and 1 on the real number line.

import { isUnitInterval } from "https://deno.land/x/isx@$VERSION/numeric/is_unit_interval.ts";
import { assert, assertFalse } from "https://deno.land/std/testing/asserts.ts";
assert(isUnitInterval(0));
assert(isUnitInterval(1.0));
assertFalse(isUnitInterval(-1));

Number subtypes

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

isOdd

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Whether the input is odd or not.

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

isEven

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Whether the input is even or not.

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

isPositiveInteger

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Whether the input is positive integer or not.

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

isNonNegativeInteger

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Whether the input is non negative integer or not.

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

Object subtypes

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

isAsyncIterable

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Whether the input is AsyncIterable or not.

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

isIterable

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Whether the input is Iterable or not.

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

Iterable subtypes

Validates a subtype of Iterable. All validate functions must satisfy ⊂ Iterable<unknown>.

isEmpty

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Wether the input is empty or not.

import { isEmpty } from "https://deno.land/x/isx@$VERSION/iterable/is_empty.ts";
import { assert } from "https://deno.land/std/testing/asserts.ts";

assert(isEmpty(""));
assert(isEmpty([]));
assert(isEmpty(new Set()));

string:

If the input is a string, it has a "" type guard.

array:

If the input is a array, it has a [] type guard.

isNotEmpty

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Whether the input is not empty or not.

import { isNotEmpty } from "https://deno.land/x/isx@$VERSION/iterable/is_not_empty.ts";
import { assert } from "https://deno.land/std/testing/asserts.ts";

assert(isNotEmpty("a"));
assert(isNotEmpty([0, 1]));

array:

If the input is a T[], it has a [T, ...T[]] type guard.

isSingle

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Whether the input is single element or not.

import { isSingle } from "https://deno.land/x/isx@$VERSION/iterable/is_single.ts";
import { assert, assertFalse } from "https://deno.land/std/testing/asserts.ts";

assert(isSingle("a"));
assert(isSingle([0]));
assertFalse(isSingle([0, 1, 2]));

array:

If the input is a T[], it has a [T] type guard.

Date subtypes

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

isValidDate

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Whether the input is valid Date or not.

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

Bundle size

Bundle size is not exact. It is only a guide.

Usually, the actual bundle size is smaller than the indicated value.

Where is mod?

There is no single entry point such as mod.

This prevents the inclusion of many unnecessary modules.

License

MIT © 2021 Tomoki Miyauchi