suggest using https://github.com/microsoft/monaco-editor as code editor
demo: https://microsoft.github.io/monaco-editor/ you can get vscode's programing/editing experience, such as: Rich IntelliSense, Validation TypeScript, JavaScript, CSS, LESS, SCSS, JSON, HTML
Basic Syntax Colorization XML, PHP, C#, C++, Razor, Markdown, Diff, Java, VB, CoffeeScript, Handlebars, Batch, Pug, F#, Lua, Powershell, Python, Ruby, SASS, R, Objective-C
code editing action CTRL+A: select all ALT + SHIFT + F: format CTRL + F: find etc.
If you can get the diff UI to work with Monaco, please be my guest.
https://github.com/AwesomeYuer/JsonStructuresDiffAssistantToolsOnline/blob/aa636257e95f7b137da773f154cc19d223568dc2/index.html#L821
demo: https://awesomeyuer.github.io/JsonStructuresDiffAssistantToolsOnline/