Use indicator line for props on block collection values of mappings

src/stringify/stringifyPair.ts

@@ -82,17 +82,16 @@ export function stringifyPair(
       str += lineComment(str, ctx.indent, commentString(keyComment))
   }
 
-  let vcb = ''
-  let valueComment = null
+  let vsb, vcb, valueComment
   if (isNode(value)) {
-    if (value.spaceBefore) vcb = '\n'
-    if (value.commentBefore) {
-      const cs = commentString(value.commentBefore)
-      vcb += `\n${indentComment(cs, ctx.indent)}`
-    }
+    vsb = !!value.spaceBefore
+    vcb = value.commentBefore
     valueComment = value.comment
-  } else if (value && typeof value === 'object') {
-    value = doc.createNode(value)
+  } else {
+    vsb = false
+    vcb = null
+    valueComment = null
+    if (value && typeof value === 'object') value = doc.createNode(value)
   }
   ctx.implicitKey = false
   if (!explicitKey && !keyComment && isScalar(value))
@@ -109,7 +108,7 @@ export function stringifyPair(
     !value.anchor
   ) {
     // If indentSeq === false, consider '- ' as part of indentation where possible
-    ctx.indent = ctx.indent.substr(2)
+    ctx.indent = ctx.indent.substring(2)
   }
 
   let valueCommentDone = false
@@ -120,13 +119,41 @@ export function stringifyPair(
     () => (chompKeep = true)
   )
   let ws = ' '
-  if (vcb || keyComment) {
-    if (valueStr === '' && !ctx.inFlow) ws = vcb === '\n' ? '\n\n' : vcb
-    else ws = `${vcb}\n${ctx.indent}`
+  if (keyComment || vsb || vcb) {
+    ws = vsb ? '\n' : ''
+    if (vcb) {
+      const cs = commentString(vcb)
+      ws += `\n${indentComment(cs, ctx.indent)}`
+    }
+    if (valueStr === '' && !ctx.inFlow) {
+      if (ws === '\n') ws = '\n\n'
+    } else {
+      ws += `\n${ctx.indent}`
+    }
   } else if (!explicitKey && isCollection(value)) {
-    const flow = valueStr[0] === '[' || valueStr[0] === '{'
-    if (!flow || valueStr.includes('\n')) ws = `\n${ctx.indent}`
-  } else if (valueStr === '' || valueStr[0] === '\n') ws = ''
+    const vs0 = valueStr[0]
+    const nl0 = valueStr.indexOf('\n')
+    const hasNewline = nl0 !== -1
+    const flow = ctx.inFlow ?? value.flow ?? value.items.length === 0
+    if (hasNewline || !flow) {
+      let hasPropsLine = false
+      if (hasNewline && (vs0 === '&' || vs0 === '!')) {
+        let sp0 = valueStr.indexOf(' ')
+        if (
+          vs0 === '&' &&
+          sp0 !== -1 &&
+          sp0 < nl0 &&
+          valueStr[sp0 + 1] === '!'
+        ) {
+          sp0 = valueStr.indexOf(' ', sp0 + 1)
+        }
+        if (sp0 === -1 || nl0 < sp0) hasPropsLine = true
+      }
+      if (!hasPropsLine) ws = `\n${ctx.indent}`
+    }
+  } else if (valueStr === '' || valueStr[0] === '\n') {
+    ws = ''
+  }
   str += ws + valueStr
 
   if (ctx.inFlow) {

tests/doc/stringify.js

@@ -253,8 +253,7 @@ foo:
     const seq = [{ foo: { bar: { baz } } }, { fe: { fi: { fo: { baz } } } }]
     expect(YAML.stringify(seq)).toBe(`- foo:
     bar:
-      baz:
-        &a1
+      baz: &a1
         a: 1
 - fe:
     fi:
@@ -364,6 +363,137 @@ z:
       )
     })
   })
+
+  describe('properties on collections in block mapping', () => {
+    test('explicit tag on block sequence', () => {
+      const src = source`
+        key: !tag
+          - one
+          - two
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(src)
+    })
+    test('explicit tag on block mapping', () => {
+      const src = source`
+        key: !tag
+          one: 1
+          two: 2
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(src)
+    })
+    test('single-line comment on block sequence', () => {
+      const src = source`
+        key: #comment
+          - one
+          - two
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(source`
+        key:
+          #comment
+          - one
+          - two
+      `)
+    })
+    test('single-line comment and explicit tag on block sequence', () => {
+      const src = source`
+        key: #comment
+          !tag
+          - one
+          - two
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(source`
+        key:
+          #comment
+          !tag
+          - one
+          - two
+      `)
+    })
+    test('explicit tag and comment on block sequence', () => {
+      const src = source`
+        key: !tag
+          #comment
+          - one
+          - two
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(source`
+        key:
+          #comment
+          !tag
+          - one
+          - two
+      `)
+    })
+    test('anchor on block sequence', () => {
+      const src = source`
+        key: &anchor
+          - one
+          - two
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(src)
+    })
+    test('anchor and explicit tag on block sequence', () => {
+      const src = source`
+        key: &anchor !tag
+          - one
+          - two
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(src)
+    })
+    test('explicit tag on empty mapping', () => {
+      const doc = new YAML.Document({ key: {} })
+      doc.get('key').tag = '!tag'
+      expect(String(doc)).toBe(source`
+        key: !tag {}
+      `)
+    })
+    test('explicit tag on single-line flow mapping', () => {
+      const src = source`
+        key: !tag { one: 1, two: 2 }
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(src)
+    })
+    test('explicit tag on multi-line flow mapping', () => {
+      const src = source`
+        key: !tag {
+          one: aaaaaaaaaa,
+          two: bbbbbbbbbb,
+          three: cccccccccc,
+          four: dddddddddd,
+          five: eeeeeeeeee
+        }
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(source`
+        key:
+          !tag {
+            one: aaaaaaaaaa,
+            two: bbbbbbbbbb,
+            three: cccccccccc,
+            four: dddddddddd,
+            five: eeeeeeeeee
+          }
+      `)
+    })
+    test('explicit tag on explicit-value block sequence', () => {
+      const src = source`
+        ? [ key ]
+        : !tag
+          - one
+          - two
+      `
+      const doc = YAML.parseDocument(src)
+      expect(String(doc)).toBe(src)
+    })
+  })
 })
 
 test('eemeli/yaml#43: Quoting colons', () => {
@@ -702,7 +832,7 @@ describe('indentSeq: false', () => {
         b: 2
       map:
         seq:
-          #sc
+        #sc
         - a
     `)
   })
@@ -714,7 +844,7 @@ describe('indentSeq: false', () => {
           b: 2
       map:
           seq:
-              #sc
+            #sc
             - a
     `)
   })
@@ -1182,15 +1312,15 @@ describe('YAML.stringify on ast Document', () => {
 })
 
 describe('flow collection padding', () => {
-  const doc = new YAML.Document();
-  doc.contents = new YAML.YAMLSeq();
-  doc.contents.items = [1, 2];
-  doc.contents.flow = true;
+  const doc = new YAML.Document()
+  doc.contents = new YAML.YAMLSeq()
+  doc.contents.items = [1, 2]
+  doc.contents.flow = true
 
   test('default', () => {
     expect(doc.toString()).toBe('[ 1, 2 ]\n')
-  });
+  })
   test('default', () => {
-    expect(doc.toString({flowCollectionPadding: false})).toBe('[1, 2]\n')
-  });
-})
+    expect(doc.toString({ flowCollectionPadding: false })).toBe('[1, 2]\n')
+  })
+})

tests/doc/types.js

@@ -778,7 +778,12 @@ date (00:00:00Z): 2002-12-14\n`)
     test('eemeli/yaml#78', () => {
       const set = new Set(['a', 'b', 'c'])
       const str = YAML.stringify({ set }, { version: '1.1' })
-      expect(str).toBe(`set:\n  !!set\n  ? a\n  ? b\n  ? c\n`)
+      expect(str).toBe(source`
+        set: !!set
+          ? a
+          ? b
+          ? c
+      `)
     })
   })