toJson tests

src/utils.js

@@ -1,7 +1,5 @@
 /**
- * Replace bigints with numbers.
- * When parsing parquet files, bigints are used to represent 64-bit integers.
- * However, JSON does not support bigints, so it's helpful to convert to numbers.
+ * Replace bigint, date, etc with legal JSON types.
  *
  * @param {any} obj object to convert
  * @returns {unknown} converted object

test/utils.test.js

@@ -0,0 +1,39 @@
+import { describe, expect, it } from 'vitest'
+import { toJson } from '../src/utils.js'
+
+describe('toJson', () => {
+  it('convert undefined to null', () => {
+    expect(toJson(undefined)).toBe(null)
+    expect(toJson(null)).toBe(null)
+  })
+
+  it('convert bigint to number', () => {
+    expect(toJson(BigInt(123))).toBe(123)
+    expect(toJson([BigInt(123), BigInt(456)])).toEqual([123, 456])
+    expect(toJson({ a: BigInt(123), b: { c: BigInt(456) } })).toEqual({ a: 123, b: { c: 456 } })
+  })
+
+  it('convert Uint8Array to array of numbers', () => {
+    expect(toJson(new Uint8Array([1, 2, 3]))).toEqual([1, 2, 3])
+  })
+
+  it('convert Date to ISO string', () => {
+    const date = new Date('2023-05-27T00:00:00Z')
+    expect(toJson(date)).toBe(date.toISOString())
+  })
+
+  it('ignore undefined properties in objects', () => {
+    expect(toJson({ a: undefined, b: BigInt(123) })).toEqual({ b: 123 })
+  })
+
+  it('return null in objects unchanged', () => {
+    expect(toJson({ a: null })).toEqual({ a: null })
+    expect(toJson([null])).toEqual([null])
+  })
+
+  it('return other types unchanged', () => {
+    expect(toJson('string')).toBe('string')
+    expect(toJson(123)).toBe(123)
+    expect(toJson(true)).toBe(true)
+  })
+})