Merge pull request #12 from jarco-develop/feature/isFunction

Add isFunction

CHANGELOG

@@ -1,3 +1,6 @@
+# 1.3.0
+- feat: isFunction
+
 # 1.2.1
 - fix: merge should not throw an error with non-plain objects in sources
 

README.md

@@ -9,6 +9,7 @@ Currently supported utils:
 - `getArrayHasIntersect` - checks if arrays have at least one common value
 - `getArrayUniq` - gets unique values form array
 - `isEmpty` - checks if value is an empty object, collection, map, or set
+- `isFunction` - checks if input is a Function object.
 - `isNil` - checks whenever value is null or undefined
 - `isPlainObject` - checks if input is object, not null object and not array object
 - `merge` - deep merge functionality for objects

index.d.ts

@@ -4,6 +4,7 @@ export function get(obj: Object, path: string | Array<string | number>, defaultV
 export function getArrayHasIntersect (arr1: Array<any>, arr2: Array<any>): boolean
 export function getArrayUniq (arr: Array<any>): Array<any>
 export function isEmpty(val: any): boolean
+export function isFunction(val: any): boolean
 export function isNil(val: any): boolean
 export function isPlainObject(val: any): boolean
 export function merge(obj: Object, ...sources: Object[]): Object

index.js

@@ -6,6 +6,7 @@ const get = require('./src/get')
 const getArrayHasIntersect = require('./src/getArrayHasIntersect')
 const getArrayUniq = require('./src/getArrayUniq')
 const isEmpty = require('./src/isEmpty')
+const isFunction = require('./src/isFunction')
 const isNil = require('./src/isNil')
 const isPlainObject = require('./src/isPlainObject')
 const merge = require('./src/merge')
@@ -21,6 +22,7 @@ module.exports = {
  getArrayHasIntersect,
  getArrayUniq,
  isEmpty,
+ isFunction,
  isNil,
  isPlainObject,
  merge,

package.json

@@ -1,6 +1,6 @@
 {
  "name": "@bitfinex/lib-js-util-base",
- "version": "1.2.1",
+ "version": "1.3.0",
  "description": "general utils",
  "main": "index.js",
  "scripts": {

src/isFunction.js

@@ -0,0 +1,5 @@
+'use strict'
+
+const isFunction = (val) => typeof val === 'function'
+
+module.exports = isFunction

test/isFunction.js

@@ -0,0 +1,57 @@
+'use strict'
+
+/* eslint-env mocha */
+
+const assert = require('assert')
+const { isFunction } = require('../index')
+
+describe('isFunction', () => {
+ it('should return true for a Function object', () => {
+ assert.strictEqual(isFunction(function () {}), true)
+ assert.strictEqual(isFunction(() => {}), true)
+ assert.strictEqual(isFunction(Object.keys), true)
+ })
+
+ it('should return `true` for async functions', () => {
+ assert.strictEqual(isFunction(async function () {}), true)
+ assert.strictEqual(isFunction(async () => {}), true)
+ })
+
+ it('should return `true` for generator functions', () => {
+ assert.strictEqual(isFunction(function * () {}), true)
+ })
+
+ it('should return `true` for the `Proxy` constructor', () => {
+ assert.strictEqual(isFunction(Proxy), true)
+ })
+
+ it('should return `true` for array view constructors', () => {
+ assert.strictEqual(isFunction(Float32Array), true)
+ assert.strictEqual(isFunction(Float64Array), true)
+ assert.strictEqual(isFunction(Int8Array), true)
+ assert.strictEqual(isFunction(Int16Array), true)
+ assert.strictEqual(isFunction(Uint8Array), true)
+ assert.strictEqual(isFunction(Uint8ClampedArray), true)
+ assert.strictEqual(isFunction(Uint16Array), true)
+ assert.strictEqual(isFunction(Uint32Array), true)
+ assert.strictEqual(isFunction(DataView), true)
+ })
+
+ it('should return `false` for non-functions', () => {
+ assert.strictEqual(isFunction(function () { return arguments }.apply(undefined, [1, 2, 3])), false) // eslint-disable-line no-useless-call
+ assert.strictEqual(isFunction([1, 2, 3]), false)
+ assert.strictEqual(isFunction(true), false)
+ assert.strictEqual(isFunction(false), false)
+ assert.strictEqual(isFunction(new Date()), false)
+ assert.strictEqual(isFunction(new Error()), false)
+ assert.strictEqual(isFunction({ a: 1 }), false)
+ assert.strictEqual(isFunction(0), false)
+ assert.strictEqual(isFunction(/x/), false)
+ assert.strictEqual(isFunction('a'), false)
+ assert.strictEqual(isFunction(Symbol('test')), false)
+ assert.strictEqual(isFunction(null), false)
+ assert.strictEqual(isFunction(undefined), false)
+ assert.strictEqual(isFunction(NaN), false)
+ assert.strictEqual(isFunction(''), false)
+ })
+})