Include circular replacer utility + add more coverage for array tests

Author: tristanmenzel

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@makerxstudio/node-common",
-  "version": "0.3.1",
+  "version": "0.4.0",
   "private": false,
   "description": "A set of MakerX core NodeJS types and utilities",
   "author": "MakerX",

src/array-helpers/distinct.spec.ts

@@ -5,7 +5,7 @@ describe('Distinct', () => {
     it('Returns only the distinct items', () => {
       const list = ['a', 'a', 'a', 'b', 'b', 'c']
 
-      const distinctList = list.filter(distinct((x) => x))
+      const distinctList = list.filter(distinct())
 
       expect(distinctList).toStrictEqual(['a', 'b', 'c'])
     })

src/array-helpers/sort-by.spec.ts

@@ -1,4 +1,4 @@
-import { sortBy } from './sort-by'
+import { combineSortFn, sortBy, sortByIgnoreCase } from './sort-by'
 
 describe('SortBy', () => {
   describe('When sorting an unordered list', () => {
@@ -10,4 +10,95 @@ describe('SortBy', () => {
       expect(sorted).toStrictEqual(['a', 'b', 'c', 'd', 'e'])
     })
   })
+  describe('When sorting an unordered list descending', () => {
+    it('It orders the list descending', () => {
+      const list = ['e', 'a', 'b', 'd', 'c']
+
+      const sorted = list.slice().sort(sortBy((x) => x, 'desc'))
+
+      expect(sorted).toStrictEqual(['e', 'd', 'c', 'b', 'a'])
+    })
+  })
+})
+
+describe('SortByIgnoreCase', () => {
+  describe('When sorting an unordered list', () => {
+    it('It orders the list', () => {
+      const list = ['e', 'a', 'B', 'D', 'c']
+
+      const sorted = list.slice().sort(sortByIgnoreCase((x) => x))
+
+      expect(sorted).toStrictEqual(['a', 'B', 'c', 'D', 'e'])
+    })
+  })
+})
+
+describe('combineSortFn', () => {
+  describe('When sorting an unordered list by multiple properties', () => {
+    it('It applies sorting rules in order', () => {
+      const users: Array<{ first: string; last: string; dob: Date }> = [
+        {
+          first: 'a',
+          last: 'b',
+          dob: new Date('2000-01-01'),
+        },
+        {
+          first: 'z',
+          last: 'a',
+          dob: new Date('2000-01-01'),
+        },
+        {
+          first: 'c',
+          last: 'b',
+          dob: new Date('2000-01-01'),
+        },
+        {
+          first: 'a',
+          last: 'a',
+          dob: new Date('2000-01-01'),
+        },
+        {
+          first: 'a',
+          last: 'a',
+          dob: new Date('2010-01-01'),
+        },
+      ]
+
+      const sorted = users.slice().sort(
+        combineSortFn(
+          sortByIgnoreCase((x) => x.last),
+          sortByIgnoreCase((x) => x.first),
+          sortBy((x) => x.dob)
+        )
+      )
+
+      expect(sorted).toStrictEqual([
+        {
+          first: 'a',
+          last: 'a',
+          dob: new Date('2000-01-01'),
+        },
+        {
+          first: 'a',
+          last: 'a',
+          dob: new Date('2010-01-01'),
+        },
+        {
+          first: 'z',
+          last: 'a',
+          dob: new Date('2000-01-01'),
+        },
+        {
+          first: 'a',
+          last: 'b',
+          dob: new Date('2000-01-01'),
+        },
+        {
+          first: 'c',
+          last: 'b',
+          dob: new Date('2000-01-01'),
+        },
+      ])
+    })
+  })
 })

src/json-helpers/get-circular-replacer.spec.ts

@@ -0,0 +1,19 @@
+import { getCircularReplacer } from './index'
+
+describe('getCircularReplacer', () => {
+  describe('When stringifying an object with a circular reference', () => {
+    const objectA = {
+      prop: 'string',
+      b: {},
+    }
+    const objectB = {
+      a: objectA,
+    }
+    objectA.b = objectB
+    it('Sets circular references to undefined', () => {
+      const str = JSON.stringify(objectA, getCircularReplacer())
+
+      expect(str).toBe(`{"prop":"string","b":{}}`)
+    })
+  })
+})

src/json-helpers/index.ts

@@ -0,0 +1,20 @@
+/**
+ * Allows you to safely stringify objects which may contain circular references
+ *
+ * Usage:
+ *
+ * JSON.stringify(someObject, getCircularReplacer(), 2)
+ */
+export const getCircularReplacer = () => {
+  const seen = new WeakSet()
+  return (_: string, value: unknown) => {
+    if (typeof value === 'object' && value !== null) {
+      if (seen.has(value)) {
+        return
+      }
+      seen.add(value)
+    }
+    if (typeof value === 'bigint') return value.toString()
+    return value
+  }
+}