Registers, triggers, and deregisters onSelectionChanged event that tracks when selections are changed in content controls.

Content Control Minimal Repro.WORD.yaml

name: Content Control Minimal Repro
description: >-
  Registers, triggers, and deregisters onSelectionChanged event that tracks when
  selections are changed in content controls.
host: WORD
api_set: {}
script:
  content: >
    $("#assemble").click(() => tryCatch(assemble));

    $("#run").click(() => tryCatch(run));


    let eventContexts = [];


    async function assemble() {
      await Word.run(async (context) => {
        var startTime = performance.now();
        const body = context.document.body;

        const range = context.document.getSelection();
        const data = [
          { name: "footnote0", message: "content0" },
          { name: "footnote1", message: "content1" },
          { name: "footnote2", message: "content2" }
        ];
        for (let item of data) {
          var contentControl = range.insertContentControl();
          contentControl.insertText(item.message, Word.InsertLocation.replace);
          // const footnote = range.insertFootnote();
          // const footnoteContentControl = footnote.body.insertContentControl();
          // footnoteContentControl.insertText(item.name, Word.InsertLocation.end);
        }

        // await context.sync();
        var endTime = performance.now();

        const contentControls = context.document.contentControls;
        contentControls.load("items");
        await context.sync();

        if (contentControls.items.length > 0) {
          for (let i = 0; i < contentControls.items.length; i++) {
            eventContexts[i] = contentControls.items[i].onSelectionChanged.add((e) =>
              contentControlSelectionChanged(e, startTime)
            );
            contentControls.items[i].track();
          }
          // await context.sync();
        }

        const cc = contentControls.getFirstOrNullObject();
        if (cc) {
          cc.select();
          // await context.sync();
        }

        console.log(`Call took ${endTime - startTime}ms`);
      });
    }


    async function run() {
      const controlData = [];
      const startTime = performance.now();
      await Word.run(async (context) => {
        const contentControls = context.document.contentControls;
        // contentControls.load(["id", "tag", "items", "fields"]);
        contentControls.load({ select: "id,tag,fields/code", expand: "fields" });
        await context.sync();

        if (contentControls.items.length === 0) {
          console.log("There aren't any content controls in this document so can't register event handlers.");
        } else {
          // for (let control of contentControls.items) {
          //   control.load("tag");
          // }
          // await context.sync();
          let fields;
          for (let control of contentControls.items) {
            try {
              fields = control.fields;
            } catch (err) {
              console.error(err);
            }
          }
          // await context.sync();
          // let fields = contentControls.items[contentControls.items.length - 1].fields;
          if (fields) {
            // for (const field of fields.items) {
            //   field.load("code");
            // }
            // await context.sync();
            // console.log("fields: " + fields);
            for (let control of contentControls.items) {
              try {
                for (const field of fields.items) {
                  const fieldCode = field.code;
                  console.log("fieldCode", fieldCode);
                }
              } catch (err) {
                console.error(err);
              }
            }
          }

          const endTime = performance.now();
          console.log("Hey, that took " + (endTime - startTime) + "ms");
        }
      });
    }


    async function contentControlSelectionChanged(event:
    Word.ContentControlSelectionChangedEventArgs, startTime) {
      await Word.run(async (context) => {
        var endTime = performance.now();
        console.log(`${event.eventType} event detected after ${endTime - startTime}ms`);
        console.log(event.ids);
      });
    }


    async function deregisterEventHandlers() {
      await Word.run(async (context) => {
        for (let i = 0; i < eventContexts.length; i++) {
          await Word.run(eventContexts[i].context, async (context) => {
            eventContexts[i].remove();
          });
        }

        await context.sync();

        eventContexts = null;
        console.log("Removed event handlers that were tracking when selection is changed in content controls.");
      });
    }


    /** Default helper for invoking an action and handling errors. */

    async function tryCatch(callback) {
      try {
        await callback();
      } catch (error) {
        // Note: In a production add-in, you'd want to notify the user through your add-in's UI.
        console.error(error);
      }
    }
  language: typescript
template:
  content: "<button id=\"assemble\" class=\"ms-Button\">\n\t  <span class=\"ms-Button-label\">Assemble</span>\n</button>\n<button id=\"run\" class=\"ms-Button\">\n    <span class=\"ms-Button-label\">Run</span>\n</button>\n"
  language: html
style:
  content: |-
    section.samples {
        margin-top: 20px;
    }

    section.samples .ms-Button, section.setup .ms-Button {
        display: block;
        margin-bottom: 5px;
        margin-left: 20px;
        min-width: 80px;
    }
  language: css
libraries: |
  https://appsforoffice.microsoft.com/lib/1/hosted/office.js
  @types/office-js

  office-ui-fabric-js@1.4.0/dist/css/fabric.min.css
  office-ui-fabric-js@1.4.0/dist/css/fabric.components.min.css

  core-js@2.4.1/client/core.min.js
  @types/core-js

  jquery@3.1.1
  @types/jquery@3.3.1