The Multi-line String Serializer tool (which makes use of the Uize.Json.MultiLineStringLiteral and Uize.Widgets.Tools.MultiLineStringSerializer.Widget modules) lets you serialize multi-line text strings to multi-line JavaScript string literal expressions that use string concatenation.

Paste some multi-line text into the "Multi-line Text" pane to see the text serialized to a multi-line JavaScript string literal expression in the "Multi-line JavaScript Expression" pane.

You can also enter a multi-line JavaScript string literal expression in the "Multi-line JavaScript Expression" pane to see the plain text version of that expression in the "Multi-line Text" pane.