[WIP] implement some functionality for commit language graph

bfcbfe59d9a93e837abcbfa2f22f330c1c2dba55

Tucker McKnight <tmcknight@instructure.com> | Sun Aug 02 2026

[WIP] implement some functionality for commit language graph

Adds "added" and "removed" fields to a commit, which has the number
of lines added and deleted in that commit hunk. This is different
from the length of the beforeText and afterText fields, since those
have newlines added to them to balance them out in the side-by-side
view. So the beforeText and afterText always have the same number
of lines in them. added and removed says what the original diff
sizes were.

This is still a WIP and I need to figure out how to have shared
language colors between this and the repo home graph, as well
as implement the "other" length. And also do something for the
average size of a commit -- a moving standard deviation?
js_templates/commits.ts:56
Before
After
src/dataTypes.ts:18
Before
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    lineNumber: number,
    beforeText: string,
    afterText: string,
⁣
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  }>
}

After
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    lineNumber: number,
    beforeText: string,
    afterText: string,
    added: number,
    removed: number,
  }>
}

src/helpers.ts:51
Before
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        if (str.startsWith(' ')) { return str.replace(" ", "") }
      }).join("\n")

⁣
      const changeObject = (lastHunkBefore.length > 1000 || lastHunkAfter.length > 1000)
        ? []
        : Diff.diffWordsWithSpace(lastHunkBefore, lastHunkAfter)
      let beforeText = ""
      let afterText = ""

⁣
⁣
      changeObject.forEach((obj) => {
        const numNewLines = obj.value.split('').filter(char => char === '\n').length
After
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        if (str.startsWith(' ')) { return str.replace(" ", "") }
      }).join("\n")

      // TODO: don't split on \n again here, do this earlier? More efficiently?
      const changeObject = (lastHunkBefore.split('\n').length > 1000 || lastHunkAfter.split('\n').length > 1000)
        ? []
        : Diff.diffWordsWithSpace(lastHunkBefore, lastHunkAfter)
      let beforeText = ""
      let afterText = ""
      let added = 0
      let removed = 0

      changeObject.forEach((obj) => {
        const numNewLines = obj.value.split('').filter(char => char === '\n').length
src/helpers.ts:63
Before
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        if (!obj.added && !obj.removed) {
          beforeText = beforeText + escape(obj.value)
          afterText = afterText + escape(obj.value)
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        }
        if (obj.added) {
          afterText = afterText + "<mark>" + escape(obj.value) + "</mark>"
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          if (numNewLines > 0) {
            let insertAt = beforeText.lastIndexOf("\n")
            insertAt = insertAt === -1 ? 0 : insertAt
After
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        if (!obj.added && !obj.removed) {
          beforeText = beforeText + escape(obj.value)
          afterText = afterText + escape(obj.value)
          added += obj.value.split('\n').length
          removed += obj.value.split('\n').length
        }
        if (obj.added) {
          afterText = afterText + "<mark>" + escape(obj.value) + "</mark>"
          added += obj.value.split('\n').length
          if (numNewLines > 0) {
            let insertAt = beforeText.lastIndexOf("\n")
            insertAt = insertAt === -1 ? 0 : insertAt
src/helpers.ts:75
Before
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        }
        if (obj.removed) {
          beforeText = beforeText + "<mark>" + escape(obj.value) + "</mark>"
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          if (numNewLines > 0) {
            let insertAt = afterText.lastIndexOf("\n")
            insertAt = insertAt === -1 ? 0 : insertAt
After
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        }
        if (obj.removed) {
          beforeText = beforeText + "<mark>" + escape(obj.value) + "</mark>"
          removed += obj.value.split('\n').length
          if (numNewLines > 0) {
            let insertAt = afterText.lastIndexOf("\n")
            insertAt = insertAt === -1 ? 0 : insertAt
src/helpers.ts:89
Before
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        lineNumber: parseInt(lines[previousHunk].match(lineNumberRegex)[1]),
        beforeText,
        afterText,
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      })
      previousFilename = ''
      previousHunk = index
After
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        lineNumber: parseInt(lines[previousHunk].match(lineNumberRegex)[1]),
        beforeText,
        afterText,
        added,
        removed,
      })
      previousFilename = ''
      previousHunk = index