Add keepIndent option to toString

Author: yjp20

src/options.ts

@@ -329,6 +329,15 @@ export type ToStringOptions = {
    */
   indentSeq?: boolean
 
+  /**
+   * Whether indentation in srcToken should be preserved.
+   *
+   * For this to work, you need to have parsed the yaml document with keepSourceTokens: true
+   *
+   * Default: `false`
+   */
+  keepIndent?: boolean
+
   /**
    * Maximum line width (set to `0` to disable folding).
    *
@@ -387,4 +396,4 @@ export type ToStringOptions = {
    * Default: `'true'`
    */
   verifyAliasOrder?: boolean
-}
+}

src/stringify/stringify.ts

@@ -50,6 +50,7 @@ export function createStringifyContext(
       falseStr: 'false',
       flowCollectionPadding: true,
       indentSeq: true,
+      keepIndent: false,
       lineWidth: 80,
       minContentWidth: 20,
       nullStr: 'null',
@@ -175,4 +176,4 @@ export function stringify(
   return isScalar(node) || str[0] === '{' || str[0] === '['
     ? `${props} ${str}`
     : `${props}\n${ctx.indent}${str}`
-}
+}

src/stringify/stringifyPair.ts

@@ -15,9 +15,9 @@ export function stringifyPair(
     allNullValues,
     doc,
     indent,
-    indentStep,
-    options: { commentString, indentSeq, simpleKeys }
+    options: { commentString, indentSeq, keepIndent, simpleKeys }
   } = ctx
+
   let keyComment = (isNode(key) && key.comment) || null
   if (simpleKeys) {
     if (keyComment) {
@@ -37,6 +37,24 @@ export function stringifyPair(
         ? key.type === Scalar.BLOCK_FOLDED || key.type === Scalar.BLOCK_LITERAL
         : typeof key === 'object'))
 
+  let indentStep = ctx.indentStep
+  if (
+    keepIndent &&
+    isNode(key) &&
+    isNode(value) &&
+    key.srcToken &&
+    value.srcToken &&
+    'indent' in key.srcToken &&
+    'indent' in value.srcToken
+  ) {
+    let diff = value.srcToken.indent - indent.length
+
+    // all elements other than YAMLSeq in block form must be indented to be valid YAML.
+    if (diff > 0 || (isSeq(value) && !value.flow)) {
+      indentStep = ' '.repeat(diff)
+    }
+  }
+
   ctx = Object.assign({}, ctx, {
     allNullValues: false,
     implicitKey: !explicitKey && (simpleKeys || !allNullValues),
@@ -166,4 +184,4 @@ export function stringifyPair(
   }
 
   return str
-}
+}

tests/doc/stringify.ts

@@ -871,6 +871,157 @@ describe('custom indent', () => {
   })
 })
 
+describe('keepIndent: true', () => {
+  test('keep object indentation', () => {
+    const src = source`
+      key:
+              super: indented
+    `
+    const doc = YAML.parseDocument(src, { keepSourceTokens: true })
+    expect(doc.toString({ keepIndent: true })).toBe(src)
+  })
+
+  test('keep array indentation', () => {
+    const src = source`
+      key:
+      - name: foo
+      - name: bar
+      - name: bam
+      - name: baz
+    `
+    const doc = YAML.parseDocument(src, { keepSourceTokens: true })
+    expect(doc.toString({ keepIndent: true })).toBe(src)
+  })
+
+  test('keep complex indentation', () => {
+    const src = source`
+      key:
+              super:
+              - name: foo
+              - name: bar
+              - name: bam
+              - name: baz
+                metadata:
+                    foo: why
+    `
+    const doc = YAML.parseDocument(src, { keepSourceTokens: true })
+    expect(doc.toString({ keepIndent: true })).toBe(src)
+  })
+
+  test('handles multiline seq flow on same line', () => {
+    const doc = YAML.parseDocument(
+      source`
+        key: [
+          aaaaaaaa,
+          bbbbbbbb,
+          cccccccc,
+          dddddddd,
+          eeeeeeee,
+          ffffffff,
+          gggggggg,
+          hhhhhhhh,
+        ]
+      `,
+      { keepSourceTokens: true }
+    )
+    expect(doc.toString({ keepIndent: true })).toBe(
+      source`
+        key:
+          [
+            aaaaaaaa,
+            bbbbbbbb,
+            cccccccc,
+            dddddddd,
+            eeeeeeee,
+            ffffffff,
+            gggggggg,
+            hhhhhhhh
+          ]
+      `
+    )
+  })
+  test('handles multiline flow on same line', () => {
+    const doc = YAML.parseDocument(
+      source`
+        key: !tag {
+          one: aaaaaaaa,
+          two: bbbbbbbb,
+          three: cccccccc,
+          four: dddddddd,
+          five: eeeeeeee
+        }
+      `,
+      { keepSourceTokens: true }
+    )
+    expect(doc.toString({ keepIndent: true })).toBe(
+      source`
+        key:
+          !tag {
+            one: aaaaaaaa,
+            two: bbbbbbbb,
+            three: cccccccc,
+            four: dddddddd,
+            five: eeeeeeee
+          }
+      `
+    )
+  })
+
+  test('handles multiline flow on next line', () => {
+    const src = source`
+      key:
+           !tag {
+             one: aaaaaaaa,
+             two: bbbbbbbb,
+             three: cccccccc,
+             four: dddddddd,
+             five: eeeeeeee
+           }
+    `
+    const doc = YAML.parseDocument(src, { keepSourceTokens: true })
+    expect(doc.toString({ keepIndent: true })).toBe(src)
+  })
+
+  test('handles multiline flow on next line', () => {
+    const src = source`
+      key:
+           !tag {
+             one: aaaaaaaa,
+             two: bbbbbbbb,
+             three: cccccccc,
+             four: dddddddd,
+             five: eeeeeeee
+           }
+    `
+    const doc = YAML.parseDocument(src, { keepSourceTokens: true })
+    expect(doc.toString({ keepIndent: true })).toBe(src)
+  })
+
+  test('handles explicit key map with no indent', () => {
+    const src = source`
+      foo:
+        ? [ key ]
+        : !tag
+        - foo
+        - bar
+    `
+    const doc = YAML.parseDocument(src, { keepSourceTokens: true })
+    expect(doc.toString({ keepIndent: true })).toBe(src)
+  })
+
+  test('handles explicit key map with indent', () => {
+    const src = source`
+      foo:
+          ? [ key ]
+          : !tag
+                - foo
+                - bar
+    `
+    const doc = YAML.parseDocument(src, { keepSourceTokens: true })
+    expect(doc.toString({ keepIndent: true })).toBe(src)
+  })
+})
+
 describe('indentSeq: false', () => {
   let obj: unknown
   beforeEach(() => {
@@ -1451,4 +1602,4 @@ describe('flow collection padding', () => {
   test('default', () => {
     expect(doc.toString({ flowCollectionPadding: false })).toBe('[1, 2]\n')
   })
-})
+})