Support cdk diff output that can be understood by many markdown renderers

[sgmorrison]

The output of a cdk diff command produces a diff summary like below:

Stack stack-name
Resources
[~] AWS::CloudWatch::Dashboard dashboard-name
 └─ [~] DashboardBody
     └─ [-] "old"
     └─ [+] "new"

When posting such a diff in a pull request to show expected changes, there is no good way to add colouring to the text. I propose we support a second output format which is compatible with the diff language support in markdown:

Stack stack-name
Resources
~ AWS::CloudWatch::Dashboard dashboard-name
~ └─ DashboardBody
-    └─ "old"
+    └─ "new"

This conveys the same information as before, but also assists in assessing planned changes.

The new format would need to be enabled with a command line flag, to retain backwards compatibility.

[indrora]

This would make for a good feature suggestion, but it would likely be a low priority in the long run.

[kaykhan]

@sgmorrison did you find a solution?

[sgmorrison]

Unfortunately not. I changed tactics instead, using snapshot tests with the snapshot checked in to version control. That way the diff is presented alongside code change diffs, and is highlighted well.