Add custom keymapping for addresses

Unlike other components, addresses use hardbreaks between lines of the address rather than new paragraphs.

This PR disables the shift+enter mapping for linebreaks and instead adds custom mapping to the enter key to insert linebreaks when in an address instead.

When the user is at the end of an address and presses enter for a second time we instead insert a paragraph and return false to let the default handler lift the paragraph out of the address.

lib/plugins.js

@@ -1,18 +1,25 @@
 import { exampleSetup } from "prosemirror-example-setup";
 import customInputRules from "./plugins/custom-input-rules";
 import editorGovspeakClass from "./plugins/editor-govspeak-class";
+import customKeymap from "./plugins/custom-keymap";
 import menu from "./plugins/menu";
 
+const mapKeys = {
+  "Mod-Enter": false,
+  "Shift-Enter": false,
+  "Ctrl-Enter": false,
 };
 
 export default (options) => {
   const plugins = [
     customInputRules(options.schema),
     editorGovspeakClass,
+    customKeymap(options.schema),
     menu(options.schema),
   ];
 
   options.menuBar = false;
+  options.mapKeys = mapKeys;
   const examplePlugins = exampleSetup(options);
   // Remove the "ProseMirror-example-setup-style" class name plugin
   examplePlugins.pop();

lib/plugins/custom-keymap.js

@@ -0,0 +1,35 @@
+import { Selection } from "prosemirror-state";
+import { keymap } from "prosemirror-keymap";
+
+const newlineInAddress = (schema) => {
+  return (state, dispatch) => {
+    const { $head, $anchor } = state.selection;
+    if (!$head.sameParent($anchor)) return false;
+
+    const paragraphParent = $head.node($head.depth - 1);
+    if (!(paragraphParent.type === schema.nodes.address)) return false;
+
+    if (
+      $head.nodeBefore.type === schema.nodes.hard_break &&
+      $head.parentOffset === $head.parent.content.size
+    ) {
+      const pos = $head.after();
+      const tr = state.tr.deleteRange(pos - 2, pos);
+      tr.replaceWith(pos - 2, pos - 2, schema.nodes.paragraph.createAndFill());
+      tr.setSelection(Selection.near(tr.doc.resolve(pos - 1), 1));
+      tr.split(pos - 1);
+      dispatch(tr.scrollIntoView());
+      return false;
+    }
+
+    const hardBreak = schema.node("hard_break");
+    dispatch(state.tr.replaceSelectionWith(hardBreak).scrollIntoView());
+    return true;
+  };
+};
+
+export default function customKeymap(schema) {
+  return keymap({
+    Enter: newlineInAddress(schema),
+  });
+}