debug markdown diff output edge cases

TODO.md

@@ -1,33 +1 @@
-
- - create production mode build and serve settings: `webpack.js` and `src/server/babel.index.js`
-
-
-## State changes
-
-main page edits input documents
-compare page views compare documents
-
-compare button:
-
-- generate id
-- post input documents to server
-- input documents copied to compare documents
-- input documents cleared
-- go to compare route
-
-edit button:
-
-- compare documents copied to input documents
-- compare documents cleared
-- go to main route
-
-client start:
-
-- load input documents from localStore
-
-server start:
-
-- load compare documents from database
-
-
-* client actually never needs to query server for compare documents... huh!
+Support for displaying and responding to `#markdown` path suffix.

src/common/selectors.js

@@ -44,20 +44,14 @@ export const isShowDifference= isShow(Show.DIFFERENCE)
 export const diff = createSelector(
   [format, safeInput],
   (format, safeInput) => {
-    return Dubdiff.plaintextDiff(safeInput.original, safeInput.final)
-/*
-    let diff = JsDiff.diffWords (input.original.replace(/ /g, ' '), input.final.replace(/ /g, ' '))
-    return diff.map(({added, removed, value})=>({added, removed, value:value.replace(/ /g, ' ')})).map(part => (
-      part.added ? <ins>{part.value}</ins> :
-      part.removed ? <del>{part.value}</del> :
-      <span>{part.value}</span> 
-    ))
-*/ 
+    if (format==Format.PLAINTEXT)
+      return Dubdiff.plaintextDiff(safeInput.original, safeInput.final)
+    else if (format==Format.MARKDOWN)
+      return Dubdiff.markdownDiff(safeInput.original, safeInput.final)
   }
 )
 
 
-
 /*
   html diff
   ---

src/common/util/EditorsDiff.js

@@ -60,4 +60,5 @@ class EditorsDiff extends Diff {
 
 export default EditorsDiff
 
-const isSpace = str => /[ ]+/.test(str)
+const isSpace = str => /[ ]+/.test(str)
+const isNewline = str => /[\n]+/.test(str)

src/common/util/dubdiff.js

@@ -44,10 +44,12 @@ export function diffToHtml(diff) {
 // In essence, moves the markdown formatting elements in or out of the inserted and deleted blocks, as appropriate
 
 //rules:
+
 // 1. if a multiline del block is followed by an ins block, 
 //    the first line of the ins block should be inserted at the end of the first line of the del block
 //    so the markdown will apply to the ins text as it should
-// 2. after a newline, if an ins or del block begins with a markdown line formatting prefix (eg. for a title or list)
+// 2. multiline ins and del blocks should be broken up into a series of single line blocks
+// 3. after a newline, if an ins or del block begins with a markdown line formatting prefix (eg. for a title or list)
 //    then that prefix should be moved out of the block
 
 //not yet implemented rules:
@@ -59,8 +61,10 @@ export function diffToHtml(diff) {
 function rewriteMarkdownDiff(diff) {  
   //apply transformation rules
   let transformedDiff = diff
-  transformedDiff= applyTransformationRule1(transformedDiff)
-  transformedDiff= applyTransformationRule2(transformedDiff)
+  transformedDiff= applyTransformationRuleMultilineDelThenIns(transformedDiff)
+  transformedDiff= applyTransformationRuleBreakUpDelIns(transformedDiff)
+  transformedDiff= applyTransformationRuleFormattingPrefix(transformedDiff)
+  transformedDiff= applyTransformationRuleRemoveEmpty(transformedDiff)
   return transformedDiff
 }
 
@@ -68,7 +72,7 @@ function rewriteMarkdownDiff(diff) {
 // 1. if a multiline del block is followed by an ins block, 
 //    the first line of the ins block should be inserted at the end of the first line of the del block
 //    so the markdown will apply to the ins text as it should
-function applyTransformationRule1(diff) {
+function applyTransformationRuleMultilineDelThenIns(diff) {
   let transformedDiff = []
 
   const B_ADDED='added', B_REMOVED='removed', B_SAME='same'
@@ -117,6 +121,46 @@ function applyTransformationRule1(diff) {
   return transformedDiff
 }
 
+//Transformation rule 2
+// 2. multiline del and ins blocks should be broken up 
+//    into a series of single line blocks
+function applyTransformationRuleBreakUpDelIns(diff) {
+  let transformedDiff = []
+
+  const B_ADDED='added', B_REMOVED='removed', B_SAME='same'
+  let blockType = null
+  let blockIsMultiline = false
+
+  //iterate the input tokens to create the intermediate representation
+  diff.forEach((block) => {
+
+    blockType = (block.added ? B_ADDED : (block.removed ? B_REMOVED : B_SAME))
+    blockIsMultiline = isMultilineDiffBlock(block)
+
+    //transform rule applys when:
+    // the current block is an ins or del and is multiline
+    if ((blockType == B_REMOVED || blockType == B_ADDED) && blockIsMultiline) {
+
+      //split the first line from the current block
+      let blockSplit = splitMultilineDiffBlock(block)
+
+      blockSplit.forEach(blockSplitLine => transformedDiff.push(blockSplitLine))
+    }
+    else {
+      //otherwise, we just add the current block to the transformed list
+      transformedDiff.push(block)
+    }
+  })
+
+  return transformedDiff
+}
+
+
+// Transformation rule number 4: remove empty blocks
+function applyTransformationRuleRemoveEmpty(diff) {
+  
+  return diff.filter(({value}) => value.length>0)
+}
 
 // matches markdown prefixes that affect the formatting of the whole subsequent line
   // ^                  - start of line
@@ -126,18 +170,18 @@ function applyTransformationRule1(diff) {
   //  |([ \t]+[\*\+-])     - unordered lists
   //  |([ \t]+[0-9]+\.)  - numeric lists
   // )?
-  // [ \t]*             - trailing whitespace
-const MARKDOWN_PREFIX =  /^([ \t]*\>)*(([ \t]*#*)|([ \t]*[\*\+-])|([ \t]*[\d]+\.))?[ \t]*/
+  // [ \t]+             - trailing whitespace
+const MARKDOWN_PREFIX =  /^([ \t]*\>)*(([ \t]*#*)|([ \t]*[\*\+-])|([ \t]*[\d]+\.))?[ \t]+/
 
 //matches strings that end with a newline followed by some whitespace
 const NEWLINE_SUFFIX = /\n\s*$/
 
-// transformation rule 2:
+// transformation rule 3:
 //    after a newline, if an ins or del block begins with a markdown line formatting prefix (eg. for a title or list)
 //    then that prefix should be moved out of the block
 //    also, if an ins block begins with a formatting prefix and follows immediately after a del block that follows a newline,
 //    the prefix should be moved out of the block _and_ an extra newline character should be added to the beginning of it
-function applyTransformationRule2(diff) {
+function applyTransformationRuleFormattingPrefix(diff) {
   let transformedDiff = []
 
   let isNewline = true
@@ -186,42 +230,21 @@ function isMultilineDiffBlock({value}) {
 //but with the string split by newlines
 //if the diff block has no newlines, an array containing only that diff will be returned
 //if the diff block has newlines, the resulting array will have a series of blocks, 
-// each of which subsequent to the first block will begin with a newline
+// consisting of the block text, interleaved with newlines
+// , 
+// each of which begin with a newline
 //if the diff block begins with a newline, the returned array will begin with an empty diff
 function splitMultilineDiffBlock({added, removed, value}) {
-  //find the indices of the diff block that coorespond to newlines
-  const splits = indicesOf(value, c => (c=='\n') )
+  let lines = value.split('\n')
+  let blocks = []
+//  lines = lines.filter(line=>line.length>0)
+  lines.forEach((line, index) => {
+    blocks.push({added, removed, value:line})
+    if (index<lines.length-1) blocks.push({value:'\n'})
+  } )
 
-  splits.push(value.length)
-
-  //create a range from each index
-  const ranges = splits.reduce(  
-    //the accumulator is a structure with the last index and the list of ranges 
-    //the ranges are a {start, end} structure 
-    ({last, ranges}, i) => {
-      ranges = ranges.concat([{start:last, end:i}])
-      return {last:i, ranges}
-    },
-    //start with the zero index and an empty array 
-    {last: 0, ranges:[]}
-  ).ranges
-
-
-  //map the ranges into blocks
-  const blocks = ranges.map(
-    //each block is the same as the given original block, but with the values split at newlines
-    ({start, end}) => ({added, removed, value:value.substring(start, end)})
-  )
-
-  //console.log({value, splits, ranges, blocks})
+  console.log(lines)
+  console.log(blocks)
 
   return blocks
-}
-
-//collect all the indices of the given string that satisfy the test function
-const indicesOf = (string, test) => string.split('').reduce( 
-  //add indexes that satisfy the test function to the array
-  (acc, x, i) => (test(x) ? acc.concat([i]) : acc ), 
-  //start with the empty array
-  []
-)
+}

test/dubdiffMarkdown.js

@@ -5,7 +5,7 @@
 
 import chai from 'chai'
 
-import {markdownDiff, diffToString} from '../src/common/util/dubdiff'
+import {markdownDiff, diffToString, diffToHtml} from '../src/common/util/dubdiff'
 
 let diff = (a,b) => diffToString(markdownDiff(a,b))
 
@@ -43,7 +43,7 @@ describe('dubdiff', () => {
 `# Title
 other`,
 `# Subtitle`
-    )).to.equal('# [-Title-]{+Subtitle+}[-\nother-]')
+    )).to.equal('# [-Title-]{+Subtitle+}\n[-other-]')
   })
 
   it('pulls prefixes out of ins or del blocks after newline',  () => {
@@ -70,5 +70,18 @@ other`,
       'This [link](https://somewhere.com) is the same.',
       'This [link](https://somewhere.org) changed.'
     )).to.equal('This [link](https://somewhere.[-com-]{+org+}) [-is the same-]{+changed+}.')
+  }) 
+  it('deletes a title' , () => {
+    expect(diff(
+      'Hello\n# Title 1\n# Title 2',
+      'Hello\n# Title 2'
+    )).to.equal('Hello\n# Title [-1-]\n# [-Title -]2',)
   })
-})
+  it('deletes a more different title' , () => {
+    expect(diff(
+      'Hello\n# Filbert\n# Title 2',
+      'Hello\n# Title 2'
+    )).to.equal('Hello\n# [-Filbert-]\n# Title 2',)
+  })
+})
+