Console should pretty-print values

The JavaScript console should pretty-print values:

• Values should be syntax highlighted
• We should print all values in a reasonable way, including functions, complex objects (e.g. jQuery collection), etc.
• As a baseline, the printing behavior for a given object should be at least as good as it is in the current built-in Chrome console

I suspect https://github.com/cvadillo/js-object-pretty-print will be of use—I’m thinking we will probably want to actually load this into the preview environment and just pass an already-pretty-printed string through the postMessage.

まず JavaScript コンソールとプレビュー環境の postMessage パスを見つけ、次に参照されている js-object-pretty-print プロジェクトを確認します。完了条件には、構文ハイライトと、関数、複雑なオブジェクト、その他の値に対する妥当な出力を含め、少なくとも Chrome 組み込みコンソールと同等の動作にする必要があります。