Function JSONDiffForFile

source/platforms/git/gitJSONToGitDSL.ts:98–155

(filename: string)

   * @param filename path of the file
   */
  const JSONDiffForFile = async (filename: string) => {
    const patchObject = await JSONPatchForFile(filename)

    if (!patchObject) {
      return {}
    }

    // Thanks to @wtgtybhertgeghgtwtg for getting this started in #175
    // The idea is to loop through all the JSON patches, then pull out the before and after from those changes.

    const { diff: outerDiff, before, after } = patchObject
    return outerDiff.reduce((accumulator, { path }) => {
      // We don't want to show the last root object, as these tend to just go directly
      // to a single value in the patch. This is fine, but not useful when showing a before/after
      const pathSteps = path.split("/")
      const backAStepPath = pathSteps.length <= 2 ? path : pathSteps.slice(0, pathSteps.length - 1).join("/")

      const diff: any = {
        // If a file is moved/renamed, the file will be in "danger.git.modified_files"
        // JSONPatchForFile will return null for the old file, so we need to check for that
        before: (before && jsonpointer.get(before, backAStepPath)) || null,
        after: (after && jsonpointer.get(after, backAStepPath)) || null,
      }

      const emptyValueOfCounterpart = (other: any) => {
        if (Array.isArray(other)) {
          return []
        } else if (isobject(diff.after)) {
          return {}
        }
        return null
      }

      const beforeValue = diff.before || emptyValueOfCounterpart(diff.after)
      const afterValue = diff.after || emptyValueOfCounterpart(diff.before)

      // If they both are arrays, add some extra metadata about what was
      // added or removed. This makes it really easy to act on specific
      // changes to JSON DSLs

      if (Array.isArray(afterValue) && Array.isArray(beforeValue)) {
        const arrayBefore = beforeValue as any[]
        const arrayAfter = afterValue as any[]

        diff.added = arrayAfter.filter((o) => !includes(arrayBefore, o))
        diff.removed = arrayBefore.filter((o) => !includes(arrayAfter, o))
        // Do the same, but for keys inside an object if they both are objects.
      } else if (isobject(afterValue) && isobject(beforeValue)) {
        const beforeKeys = Object.keys(beforeValue) as string[]
        const afterKeys = Object.keys(afterValue) as string[]
        diff.added = afterKeys.filter((o) => !includes(beforeKeys, o))
        diff.removed = beforeKeys.filter((o) => !includes(afterKeys, o))
      }

      jsonpointer.set(accumulator, backAStepPath, diff)
      return accumulator
    }, Object.create(null))
  }