chore: initial commit

test/index.test.ts

@@ -0,0 +1,474 @@
+import { describe, expect, it } from 'vitest'
+import { encode } from '../src/index'
+
+describe('primitives', () => {
+  it('encodes safe strings without quotes', () => {
+    expect(encode('hello')).toBe('hello')
+    expect(encode('Ada_99')).toBe('Ada_99')
+  })
+
+  it('quotes empty string', () => {
+    expect(encode('')).toBe('""')
+  })
+
+  it('quotes strings that look like booleans or numbers', () => {
+    expect(encode('true')).toBe('"true"')
+    expect(encode('false')).toBe('"false"')
+    expect(encode('null')).toBe('"null"')
+    expect(encode('42')).toBe('"42"')
+    expect(encode('-3.14')).toBe('"-3.14"')
+    expect(encode('1e-6')).toBe('"1e-6"')
+    expect(encode('05')).toBe('"05"')
+  })
+
+  it('escapes control characters in strings', () => {
+    expect(encode('line1\nline2')).toBe('"line1\\nline2"')
+    expect(encode('tab\there')).toBe('"tab\\there"')
+    expect(encode('return\rcarriage')).toBe('"return\\rcarriage"')
+    expect(encode('C:\\Users\\path')).toBe('"C:\\\\Users\\\\path"')
+  })
+
+  it('quotes strings with structural characters', () => {
+    expect(encode('[3]: x,y')).toBe('"[3]: x,y"')
+    expect(encode('- item')).toBe('"- item"')
+    expect(encode('[test]')).toBe('"[test]"')
+    expect(encode('{key}')).toBe('"{key}"')
+  })
+
+  it('handles Unicode and emoji', () => {
+    expect(encode('café')).toBe('café')
+    expect(encode('你好')).toBe('你好')
+    expect(encode('🚀')).toBe('🚀')
+    expect(encode('hello 👋 world')).toBe('hello 👋 world')
+  })
+
+  it('encodes numbers', () => {
+    expect(encode(42)).toBe('42')
+    expect(encode(3.14)).toBe('3.14')
+    expect(encode(-7)).toBe('-7')
+    expect(encode(0)).toBe('0')
+  })
+
+  it('handles special numeric values', () => {
+    expect(encode(-0)).toBe('0')
+    expect(encode(1e6)).toBe('1000000')
+    expect(encode(1e-6)).toBe('0.000001')
+    expect(encode(1e20)).toBe('100000000000000000000')
+    expect(encode(Number.MAX_SAFE_INTEGER)).toBe('9007199254740991')
+  })
+
+  it('encodes booleans', () => {
+    expect(encode(true)).toBe('true')
+    expect(encode(false)).toBe('false')
+  })
+
+  it('encodes null', () => {
+    expect(encode(null)).toBe('null')
+  })
+})
+
+describe('objects (simple)', () => {
+  it('preserves key order in objects', () => {
+    const obj = {
+      id: 123,
+      name: 'Ada',
+      active: true,
+    }
+    expect(encode(obj)).toBe('id: 123\nname: Ada\nactive: true')
+  })
+
+  it('encodes null values in objects', () => {
+    const obj = { id: 123, value: null }
+    expect(encode(obj)).toBe('id: 123\nvalue: null')
+  })
+
+  it('encodes empty objects as empty string', () => {
+    expect(encode({})).toBe('')
+  })
+
+  it('quotes string values with special characters', () => {
+    expect(encode({ note: 'a:b' })).toBe('note: "a:b"')
+    expect(encode({ note: 'a,b' })).toBe('note: "a,b"')
+    expect(encode({ text: 'line1\nline2' })).toBe('text: "line1\\nline2"')
+    expect(encode({ text: 'say "hello"' })).toBe('text: "say \\"hello\\""')
+  })
+
+  it('quotes string values with leading/trailing spaces', () => {
+    expect(encode({ text: ' padded ' })).toBe('text: " padded "')
+    expect(encode({ text: '  ' })).toBe('text: "  "')
+  })
+
+  it('quotes string values that look like booleans/numbers', () => {
+    expect(encode({ v: 'true' })).toBe('v: "true"')
+    expect(encode({ v: '42' })).toBe('v: "42"')
+    expect(encode({ v: '-7.5' })).toBe('v: "-7.5"')
+  })
+})
+
+describe('objects (keys)', () => {
+  it('quotes keys with special characters', () => {
+    expect(encode({ 'order:id': 7 })).toBe('"order:id": 7')
+    expect(encode({ '[index]': 5 })).toBe('"[index]": 5')
+    expect(encode({ '{key}': 5 })).toBe('"{key}": 5')
+    expect(encode({ 'a,b': 1 })).toBe('"a,b": 1')
+  })
+
+  it('quotes keys with spaces or leading hyphens', () => {
+    expect(encode({ 'full name': 'Ada' })).toBe('"full name": Ada')
+    expect(encode({ '-lead': 1 })).toBe('"-lead": 1')
+    expect(encode({ ' a ': 1 })).toBe('" a ": 1')
+  })
+
+  it('quotes numeric keys', () => {
+    expect(encode({ 123: 'x' })).toBe('"123": x')
+  })
+
+  it('quotes empty string key', () => {
+    expect(encode({ '': 1 })).toBe('"": 1')
+  })
+
+  it('escapes control characters in keys', () => {
+    expect(encode({ 'line\nbreak': 1 })).toBe('"line\\nbreak": 1')
+    expect(encode({ 'tab\there': 2 })).toBe('"tab\\there": 2')
+  })
+
+  it('escapes quotes in keys', () => {
+    expect(encode({ 'he said "hi"': 1 })).toBe('"he said \\"hi\\"": 1')
+  })
+})
+
+describe('nested objects', () => {
+  it('encodes deeply nested objects', () => {
+    const obj = {
+      a: {
+        b: {
+          c: 'deep',
+        },
+      },
+    }
+    expect(encode(obj)).toBe('a:\n  b:\n    c: deep')
+  })
+
+  it('encodes empty nested object', () => {
+    expect(encode({ user: {} })).toBe('user:')
+  })
+})
+
+describe('arrays of primitives', () => {
+  it('encodes string arrays inline', () => {
+    const obj = { tags: ['admin', 'ops'] }
+    expect(encode(obj)).toBe('tags[2]: admin,ops')
+  })
+
+  it('encodes number arrays inline', () => {
+    const obj = { nums: [1, 2, 3] }
+    expect(encode(obj)).toBe('nums[3]: 1,2,3')
+  })
+
+  it('encodes mixed primitive arrays inline', () => {
+    const obj = { data: ['x', 'y', true, 10] }
+    expect(encode(obj)).toBe('data[4]: x,y,true,10')
+  })
+
+  it('encodes empty arrays', () => {
+    const obj = { items: [] }
+    expect(encode(obj)).toBe('items[0]:')
+  })
+
+  it('handles empty string in arrays', () => {
+    const obj = { items: [''] }
+    expect(encode(obj)).toBe('items[1]: ""')
+    const obj2 = { items: ['a', '', 'b'] }
+    expect(encode(obj2)).toBe('items[3]: a,"",b')
+  })
+
+  it('handles whitespace-only strings in arrays', () => {
+    const obj = { items: [' ', '  '] }
+    expect(encode(obj)).toBe('items[2]: " ","  "')
+  })
+
+  it('quotes array strings with special characters', () => {
+    const obj = { items: ['a', 'b,c', 'd:e'] }
+    expect(encode(obj)).toBe('items[3]: a,"b,c","d:e"')
+  })
+
+  it('quotes strings that look like booleans/numbers in arrays', () => {
+    const obj = { items: ['x', 'true', '42', '-3.14'] }
+    expect(encode(obj)).toBe('items[4]: x,"true","42","-3.14"')
+  })
+
+  it('quotes strings with structural meanings in arrays', () => {
+    const obj = { items: ['[5]', '- item', '{key}'] }
+    expect(encode(obj)).toBe('items[3]: "[5]","- item","{key}"')
+  })
+})
+
+describe('arrays of objects (tabular and list items)', () => {
+  it('encodes arrays of similar objects in tabular format', () => {
+    const obj = {
+      items: [
+        { sku: 'A1', qty: 2, price: 9.99 },
+        { sku: 'B2', qty: 1, price: 14.5 },
+      ],
+    }
+    expect(encode(obj)).toBe('items[2]{sku,qty,price}:\n  A1,2,9.99\n  B2,1,14.5')
+  })
+
+  it('handles null values in tabular format', () => {
+    const obj = {
+      items: [
+        { id: 1, value: null },
+        { id: 2, value: 'test' },
+      ],
+    }
+    expect(encode(obj)).toBe('items[2]{id,value}:\n  1,null\n  2,test')
+  })
+
+  it('quotes strings in tabular rows when needed', () => {
+    const obj = {
+      items: [
+        { sku: 'A,1', desc: 'cool', qty: 2 },
+        { sku: 'B2', desc: 'wip: test', qty: 1 },
+      ],
+    }
+    expect(encode(obj)).toBe('items[2]{sku,desc,qty}:\n  "A,1",cool,2\n  B2,"wip: test",1')
+  })
+
+  it('quotes ambiguous strings in tabular rows', () => {
+    const obj = {
+      items: [
+        { id: 1, status: 'true' },
+        { id: 2, status: 'false' },
+      ],
+    }
+    expect(encode(obj)).toBe('items[2]{id,status}:\n  1,"true"\n  2,"false"')
+  })
+
+  it('handles tabular arrays with keys needing quotes', () => {
+    const obj = {
+      items: [
+        { 'order:id': 1, 'full name': 'Ada' },
+        { 'order:id': 2, 'full name': 'Bob' },
+      ],
+    }
+    expect(encode(obj)).toBe('items[2]{"order:id","full name"}:\n  1,Ada\n  2,Bob')
+  })
+
+  it('uses list format for objects with different fields', () => {
+    const obj = {
+      items: [
+        { id: 1, name: 'First' },
+        { id: 2, name: 'Second', extra: true },
+      ],
+    }
+    expect(encode(obj)).toBe(
+      'items[2]:\n'
+      + '  - id: 1\n'
+      + '    name: First\n'
+      + '  - id: 2\n'
+      + '    name: Second\n'
+      + '    extra: true',
+    )
+  })
+
+  it('uses list format for objects with nested values', () => {
+    const obj = {
+      items: [
+        { id: 1, nested: { x: 1 } },
+      ],
+    }
+    expect(encode(obj)).toBe(
+      'items[1]:\n'
+      + '  - id: 1\n'
+      + '    nested:\n'
+      + '      x: 1',
+    )
+  })
+
+  it('uses field order from first object for tabular headers', () => {
+    const obj = {
+      items: [
+        { a: 1, b: 2, c: 3 },
+        { c: 30, b: 20, a: 10 },
+      ],
+    }
+    expect(encode(obj)).toBe('items[2]{a,b,c}:\n  1,2,3\n  10,20,30')
+  })
+
+  it('uses list format for one object with nested column', () => {
+    const obj = {
+      items: [
+        { id: 1, data: 'string' },
+        { id: 2, data: { nested: true } },
+      ],
+    }
+    expect(encode(obj)).toBe(
+      'items[2]:\n'
+      + '  - id: 1\n'
+      + '    data: string\n'
+      + '  - id: 2\n'
+      + '    data:\n'
+      + '      nested: true',
+    )
+  })
+})
+
+describe('arrays of arrays (primitives only)', () => {
+  it('encodes nested arrays of primitives', () => {
+    const obj = {
+      pairs: [['a', 'b'], ['c', 'd']],
+    }
+    expect(encode(obj)).toBe('pairs[2]:\n  - [2]: a,b\n  - [2]: c,d')
+  })
+
+  it('quotes nested array strings when needed', () => {
+    const obj = {
+      pairs: [['a', 'b'], ['c,d', 'e:f', 'true']],
+    }
+    expect(encode(obj)).toBe('pairs[2]:\n  - [2]: a,b\n  - [3]: "c,d","e:f","true"')
+  })
+
+  it('handles empty inner arrays', () => {
+    const obj = {
+      pairs: [[], []],
+    }
+    expect(encode(obj)).toBe('pairs[2]:\n  - [0]:\n  - [0]:')
+  })
+
+  it('handles mixed-length inner arrays', () => {
+    const obj = {
+      pairs: [[1], [2, 3]],
+    }
+    expect(encode(obj)).toBe('pairs[2]:\n  - [1]: 1\n  - [2]: 2,3')
+  })
+})
+
+describe('root arrays', () => {
+  it('encodes arrays of primitives at root level', () => {
+    const arr = ['x', 'y', 'true', true, 10]
+    expect(encode(arr)).toBe('[5]: x,y,"true",true,10')
+  })
+
+  it('encodes arrays of similar objects in tabular format', () => {
+    const arr = [{ id: 1 }, { id: 2 }]
+    expect(encode(arr)).toBe('[2]{id}:\n  1\n  2')
+  })
+
+  it('encodes arrays of different objects in list format', () => {
+    const arr = [{ id: 1 }, { id: 2, name: 'Ada' }]
+    expect(encode(arr)).toBe('[2]:\n  - id: 1\n  - id: 2\n    name: Ada')
+  })
+
+  it('encodes empty arrays at root level', () => {
+    expect(encode([])).toBe('[0]:')
+  })
+
+  it('encodes root arrays of arrays', () => {
+    const arr = [[1, 2], []]
+    expect(encode(arr)).toBe('[2]:\n  - [2]: 1,2\n  - [0]:')
+  })
+})
+
+describe('complex structures', () => {
+  it('encodes objects with mixed arrays and nested objects', () => {
+    const obj = {
+      user: {
+        id: 123,
+        name: 'Ada',
+        tags: ['admin', 'ops'],
+        active: true,
+        prefs: [],
+      },
+    }
+    expect(encode(obj)).toBe(
+      'user:\n'
+      + '  id: 123\n'
+      + '  name: Ada\n'
+      + '  tags[2]: admin,ops\n'
+      + '  active: true\n'
+      + '  prefs[0]:',
+    )
+  })
+})
+
+describe('mixed arrays', () => {
+  it('uses list format for arrays mixing primitives and objects', () => {
+    const obj = {
+      items: [1, { a: 1 }, 'text'],
+    }
+    expect(encode(obj)).toBe(
+      'items[3]:\n'
+      + '  - 1\n'
+      + '  - a: 1\n'
+      + '  - text',
+    )
+  })
+
+  it('uses list format for arrays mixing objects and arrays', () => {
+    const obj = {
+      items: [{ a: 1 }, [1, 2]],
+    }
+    expect(encode(obj)).toBe(
+      'items[2]:\n'
+      + '  - a: 1\n'
+      + '  - [2]: 1,2',
+    )
+  })
+})
+
+describe('whitespace and formatting invariants', () => {
+  it('produces no trailing spaces at end of lines', () => {
+    const obj = {
+      user: {
+        id: 123,
+        name: 'Ada',
+      },
+      items: ['a', 'b'],
+    }
+    const result = encode(obj)
+    const lines = result.split('\n')
+    for (const line of lines) {
+      expect(line).not.toMatch(/ $/)
+    }
+  })
+
+  it('produces no trailing newline at end of output', () => {
+    const obj = { id: 123 }
+    const result = encode(obj)
+    expect(result).not.toMatch(/\n$/)
+  })
+})
+
+describe('non-JSON-serializable values', () => {
+  it('converts BigInt to string', () => {
+    expect(encode(BigInt(123))).toBe('123')
+    expect(encode({ id: BigInt(456) })).toBe('id: 456')
+  })
+
+  it('converts Date to ISO string', () => {
+    const date = new Date('2025-01-01T00:00:00.000Z')
+    expect(encode(date)).toBe('"2025-01-01T00:00:00.000Z"')
+    expect(encode({ created: date })).toBe('created: "2025-01-01T00:00:00.000Z"')
+  })
+
+  it('converts undefined to null', () => {
+    expect(encode(undefined)).toBe('null')
+    expect(encode({ value: undefined })).toBe('value: null')
+  })
+
+  it('converts non-finite numbers to null', () => {
+    expect(encode(Infinity)).toBe('null')
+    expect(encode(-Infinity)).toBe('null')
+    expect(encode(Number.NaN)).toBe('null')
+  })
+
+  it('converts functions to null', () => {
+    expect(encode(() => {})).toBe('null')
+    expect(encode({ fn: () => {} })).toBe('fn: null')
+  })
+
+  it('converts symbols to null', () => {
+    expect(encode(Symbol('test'))).toBe('null')
+    expect(encode({ sym: Symbol('test') })).toBe('sym: null')
+  })
+})