✨ Add isEmpty function

docs/api/empty/index.md

@@ -0,0 +1,17 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+
+
+## Empty type
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+Alias for Empty values
+
+<b>Signature:</b>
+
+```typescript
+type Empty = "" | [
+] | {};
+```

docs/api/index.md

@@ -25,6 +25,7 @@
 |  [inc](./inc/) | Increments its argument. |
 |  [isBigint](./isbigint/) | Whatever argument is type of <code>bigint</code> or not. |
 |  [isBoolean](./isboolean/) | Whatever argument is type of <code>boolean</code> or not. |
+|  [isEmpty](./isempty/) | <b><i>(BETA)</i></b> Returns <code>true</code> if the given value is its type's empty value; otherwise <code>false</code>. |
 |  [isFunction](./isfunction/) | Whatever argument is type of <code>function</code> or not. |
 |  [isNill](./isnill/) | Whatever argument is type of <code>undefined</code> or <code>null</code>. |
 |  [isNull](./isnull/) | Whatever argument is type of <code>null</code> or not. |
@@ -59,6 +60,7 @@
 |  Type Alias | Description |
 |  --- | --- |
 |  [AnyFn](./anyfn/) | Type of any function |
+|  [Empty](./empty/) | <b><i>(BETA)</i></b> Alias for Empty values |
 |  [endsWith](./endswith/) |  |
 |  [Ord](./ord/) | Abbreviation for Ordinal |
 |  [Primitive](./primitive/) | Alias for Primitive values types |

docs/api/isempty/index.md

@@ -0,0 +1,34 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+
+
+## isEmpty variable
+
+> This API is provided as a preview for developers and may change based on feedback that we receive. Do not use this API in a production environment.
+> 
+
+Returns `true` if the given value is its type's empty value; otherwise `false`<!-- -->.
+
+<b>Signature:</b>
+
+```typescript
+isEmpty: (val: unknown) => val is Empty
+```
+
+## Remarks
+
+The definition of Empty - `''` - `{}` - `[]`
+
+## Example
+
+
+```ts
+isEmpty('') // true
+isEmpty({}) // true
+isEmpty([]) // true
+
+isEmpty('hello world') // false
+isEmpty(1000) // false
+
+```
+

mod.ts

@@ -16,6 +16,7 @@ export { identity } from './src/identity.ts'
 export { inc } from './src/inc.ts'
 export { isBigint } from './src/isBigint.ts'
 export { isBoolean } from './src/isBoolean.ts'
+export { isEmpty } from './src/isEmpty.ts'
 export { isFunction } from './src/isFunction.ts'
 export { isNill } from './src/isNill.ts'
 export { isNull } from './src/isNull.ts'
@@ -42,6 +43,6 @@ export { sum } from './src/sum.ts'
 export { T } from './src/T.ts'
 export { tail } from './src/tail.ts'
 export { trim } from './src/trim.ts'
-export type { AnyFn, Ord, Primitive } from './src/types.ts'
+export type { AnyFn, Empty, Ord, Primitive } from './src/types.ts'
 export { upperCase } from './src/upperCase.ts'
 export { xor } from './src/xor.ts'

src/isEmpty.ts

@@ -0,0 +1,44 @@
+import { and } from './and.ts'
+import { isObject } from './isObject.ts'
+import { isString } from './isString.ts'
+import { length } from './length.ts'
+import { Empty } from './types/index.ts'
+
+/**
+ * Returns `true` if the given value is its type's empty value; otherwise `false`.
+ *
+ * @param val - input any value
+ * @returns The result of empty or not
+ *
+ * @remarks
+ * The definition of Empty
+ * - `''`
+ * - `{}`
+ * - `[]`
+ *
+ * @example
+ * ```ts
+ * isEmpty('') // true
+ * isEmpty({}) // true
+ * isEmpty([]) // true
+ *
+ * isEmpty('hello world') // false
+ * isEmpty(1000) // false
+ * ```
+ *
+ * @beta
+ */
+
+// eslint-disable-next-line @typescript-eslint/ban-types
+const isEmpty = (val: unknown): val is Empty => {
+  if (isString(val)) return !length(val)
+  else if (Array.isArray(val)) return !length(val)
+  else if (isObject(val))
+    return and(
+      !length(Object.keys(val as Record<string, unknown>)),
+      (val as Record<string, unknown>).constructor === Object
+    )
+  else return false
+}
+
+export { isEmpty }

src/types/index.ts

@@ -29,5 +29,13 @@ export type Primitive =
  * @public
  */
 export type Ord = string | number | bigint | boolean | Date
+
+/**
+ * Alias for Empty values
+ *
+ * @beta
+ */
+export type Empty = '' | [] | {}
+
 export type InferArray<T> = T extends (infer R)[] ? R : never
 export type Whitespace = ' ' | '\t' | '\n'

test/isEmpty.spec.ts

@@ -0,0 +1,47 @@
+import {
+  BIG1,
+  DATE,
+  EMPTY_ARRAY,
+  EMPTY_OBJECT,
+  EMPTY_STRING,
+  MAP,
+  ONE,
+  SET,
+  SYMBOL,
+  VOID_FN,
+  VOID_PROMISE,
+  WEAK_MAP,
+  WEAK_SET,
+  ZERO
+} from '@test'
+
+import { isEmpty } from '@/isEmpty'
+describe('isEmpty', () => {
+  const table: [unknown, boolean][] = [
+    [BIG1, false],
+    [ZERO, false],
+    [ONE, false],
+    [EMPTY_STRING, true],
+    [EMPTY_OBJECT, true],
+    [EMPTY_ARRAY, true],
+    [MAP, false],
+    [SET, false],
+    ['test', false],
+    [false, false],
+    [true, false],
+    [SYMBOL, false],
+    [null, false],
+    [undefined, false],
+    [{ nest: {} }, false],
+    [[[]], false],
+    [WEAK_MAP, false],
+    [WEAK_SET, false],
+    [VOID_FN, false],
+    [VOID_PROMISE, false],
+    [DATE, false]
+  ]
+
+  it.each(table)('isEmpty(%s) -> %s', (val, expected) => {
+    expect(isEmpty(val)).toEqual(expected)
+  })
+})