fix: clarify the definition of isDefined (#815)

Author: TCL735

giraffe/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@influxdata/giraffe",
-  "version": "2.36.0",
+  "version": "2.36.1",
   "main": "dist/index.js",
   "module": "dist/index.js",
   "license": "MIT",

giraffe/src/utils/isDefined.test.ts

@@ -0,0 +1,49 @@
+import {isDefined, isDefinedOrNaN} from './isDefined'
+
+describe('utils/isDefined', () => {
+  describe('isDefined', () => {
+    it('handles falsy input', () => {
+      expect(isDefined()).toEqual(false)
+      expect(isDefined(null)).toEqual(false)
+      expect(isDefined(undefined)).toEqual(false)
+      expect(isDefined(NaN)).toEqual(false)
+
+      expect(isDefined(false)).toEqual(true)
+      expect(isDefined('')).toEqual(true)
+      expect(isDefined(0)).toEqual(true)
+    })
+
+    it('handles other input', () => {
+      expect(isDefined(true)).toEqual(true)
+      expect(isDefined('string')).toEqual(true)
+      expect(isDefined(1)).toEqual(true)
+      expect(isDefined({})).toEqual(true)
+      expect(isDefined([])).toEqual(true)
+      expect(isDefined(() => {})).toEqual(true)
+      expect(isDefined(Symbol())).toEqual(true)
+    })
+  })
+
+  describe('isDefinedOrNaN', () => {
+    it('handles falsy input', () => {
+      expect(isDefinedOrNaN()).toEqual(false)
+      expect(isDefinedOrNaN(null)).toEqual(false)
+      expect(isDefinedOrNaN(undefined)).toEqual(false)
+
+      expect(isDefinedOrNaN(NaN)).toEqual(true)
+      expect(isDefinedOrNaN(false)).toEqual(true)
+      expect(isDefinedOrNaN('')).toEqual(true)
+      expect(isDefinedOrNaN(0)).toEqual(true)
+    })
+
+    it('handles other input', () => {
+      expect(isDefinedOrNaN(true)).toEqual(true)
+      expect(isDefinedOrNaN('string')).toEqual(true)
+      expect(isDefinedOrNaN(1)).toEqual(true)
+      expect(isDefinedOrNaN({})).toEqual(true)
+      expect(isDefinedOrNaN([])).toEqual(true)
+      expect(isDefinedOrNaN(() => {})).toEqual(true)
+      expect(isDefinedOrNaN(Symbol())).toEqual(true)
+    })
+  })
+})

giraffe/src/utils/isDefined.ts

@@ -1 +1,4 @@
-export const isDefined = (x: any) => x !== null && x !== undefined && !isNaN(x)
+export const isDefined = (x?: any) =>
+  x !== null && x !== undefined && !Number.isNaN(x)
+
+export const isDefinedOrNaN = (x?: any) => x !== null && x !== undefined

stories/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@influxdata/giraffe-stories",
-  "version": "2.36.0",
+  "version": "2.36.1",
   "license": "MIT",
   "repository": {
     "type": "git",