feat: add quoteStrings option to force quoting strings in encoder (#102)

packages/toon/src/encode/encoders.ts

@@ -186,9 +186,9 @@ export function* encodeArrayOfArraysAsListItemsLines(
   }
 }
 
-export function encodeInlineArrayLine(values: readonly JsonPrimitive[], delimiter: string, prefix?: string): string {
+export function encodeInlineArrayLine(values: readonly JsonPrimitive[], delimiter: string, prefix?: string, quoteStrings?: boolean): string {
   const header = formatHeader(values.length, { key: prefix, delimiter })
-  const joinedValue = encodeAndJoinPrimitives(values, delimiter)
+  const joinedValue = encodeAndJoinPrimitives(values, delimiter, quoteStrings)
 
   if (values.length === 0)
     return header

packages/toon/src/encode/primitives.ts

@@ -5,7 +5,8 @@ import { isSafeUnquoted, isValidUnquotedKey } from '../shared/validation'
 
 // #region Primitive encoding
 
-export function encodePrimitive(value: JsonPrimitive, delimiter?: string): string {
+
+export function encodePrimitive(value: JsonPrimitive, delimiter?: string, quoteStrings?: boolean): string {
   if (value === null) {
     return NULL_LITERAL
   }
@@ -18,14 +19,17 @@ export function encodePrimitive(value: JsonPrimitive, delimiter?: string): strin
     return String(value)
   }
 
-  return encodeStringLiteral(value, delimiter)
+  return encodeStringLiteral(value, delimiter, quoteStrings)
 }
 
-export function encodeStringLiteral(value: string, delimiter: string = DEFAULT_DELIMITER): string {
+
+export function encodeStringLiteral(value: string, delimiter: string = DEFAULT_DELIMITER, quoteStrings?: boolean): string {
+  if (quoteStrings) {
+    return `${DOUBLE_QUOTE}${escapeString(value)}${DOUBLE_QUOTE}`
+  }
   if (isSafeUnquoted(value, delimiter)) {
     return value
   }
-
   return `${DOUBLE_QUOTE}${escapeString(value)}${DOUBLE_QUOTE}`
 }
 
@@ -45,8 +49,8 @@ export function encodeKey(key: string): string {
 
 // #region Value joining
 
-export function encodeAndJoinPrimitives(values: readonly JsonPrimitive[], delimiter: string = DEFAULT_DELIMITER): string {
-  return values.map(v => encodePrimitive(v, delimiter)).join(delimiter)
+export function encodeAndJoinPrimitives(values: readonly JsonPrimitive[], delimiter: string = DEFAULT_DELIMITER, quoteStrings?: boolean): string {
+  return values.map(v => encodePrimitive(v, delimiter, quoteStrings)).join(delimiter)
 }
 
 // #endregion

packages/toon/src/index.ts

@@ -218,6 +218,7 @@ function resolveOptions(options?: EncodeOptions): ResolvedEncodeOptions {
     delimiter: options?.delimiter ?? DEFAULT_DELIMITER,
     keyFolding: options?.keyFolding ?? 'off',
     flattenDepth: options?.flattenDepth ?? Number.POSITIVE_INFINITY,
+    quoteStrings: options?.quoteStrings ?? false,
     replacer: options?.replacer,
   }
 }

packages/toon/src/types.ts

@@ -74,6 +74,12 @@ export interface EncodeOptions {
    * @default Infinity
    */
   flattenDepth?: number
+    /**
+   * Always wrap string values in quotes during encoding.
+   * Useful for consistent string serialization or when building formats that require strict quoting.
+   * @default false
+   */
+  quoteStrings?: boolean
   /**
    * A function to transform or filter values during encoding.
    * Called for the root value and every nested property/element.

packages/toon/test/encode.test.ts

@@ -43,11 +43,37 @@ for (const fixtures of fixtureFiles) {
   })
 }
 
+
 function resolveEncodeOptions(options?: TestCase['options']): ResolvedEncodeOptions {
   return {
     indent: options?.indent ?? 2,
     delimiter: options?.delimiter ?? DEFAULT_DELIMITER,
     keyFolding: options?.keyFolding ?? 'off',
     flattenDepth: options?.flattenDepth ?? Number.POSITIVE_INFINITY,
+    quoteStrings: options?.quoteStrings ?? false,
   }
 }
+
+describe('encode (quoteStrings option)', () => {
+  it('should quote all string values when quoteStrings is true', () => {
+    const input = { a: 'foo', b: 'bar baz', c: 42, d: true }
+    const expected = 'a: "foo"\nb: "bar baz"\nc: 42\nd: true'
+    const result = encode(input, { quoteStrings: true })
+    expect(result).toBe(expected)
+  })
+
+  it('should quote strings in arrays when quoteStrings is true', () => {
+    const input = { arr: ['x', 'y z', 'w'] }
+    const expected = 'arr[3]: "x","y z","w"'
+    const result = encode(input, { quoteStrings: true })
+    expect(result).toBe(expected)
+  })
+
+  it('should not quote strings when quoteStrings is false (default)', () => {
+    const input = { a: 'foo', b: 'bar baz', c: 42 }
+    // Only b should be quoted because it contains a space
+    const expected = 'a: foo\nb: "bar baz"\nc: 42'
+    const result = encode(input)
+    expect(result).toBe(expected)
+  })
+})