jupyter-weave.js

// An extension to evaluate `${Python}` in Markdown cells

define(["base/js/namespace"], function(Jupyter) {
  function load_ipython_extension() {
    Jupyter.notebook.events.on("rendered.MarkdownCell", (event, data) => {
      let cell = data.cell;
      renderCell(cell);
    });

    Jupyter.notebook.events.on("kernel_ready.Kernel", () => {
      renderAllCells();
    });

    Jupyter.notebook.events.on("finished_execute.CodeCell", () => {
      console.log("got finish event");
      renderAllCells();
    });
  }

  function renderAllCells() {
    let cells = Jupyter.notebook.get_cells();
    for (let cell of cells) {
      if (cell.cell_type !== "markdown" || !cell.rendered) {
        continue;
      }
      renderCell(cell);
    }
  }

  function renderCell(cell) {
    let contentEl = cell.element[0].querySelector(".text_cell_render.rendered_html");
    for (let codeEl of contentEl.querySelectorAll("code, span.rendered_code")) {
      let code;
      if (codeEl.tagName === "CODE") {
        code = codeEl.textContent;
        if (!code.startsWith("${") || !code.endsWith("}")) {
          continue;
        }
        code = code.substr(2, code.length-3);
      } else {
        code = codeEl.title;
      }
      let startTime = Date.now();
      let outputCalled = false;
      let callbacks = {
        clear_on_done: false,
        shell: {
          reply: (msg) => {
            if (!outputCalled) {
              codeEl.title = "Note: expression had no result";
              codeEl.style.color = "#900";
            }
          }
        },
        iopub: {
          output: (output) => {
            outputCalled = true;
            let totalTime = Date.now() - startTime;
            if (output.content.ename) {
              // Got an exception, ignore since this will be common
              console.error(`${output.content.ename} in expression ${code}: ${output.content.evalue}`);
              let traceback = output.content.traceback.join("\n");
              traceback = traceback.replace(/\u001b[^m]+m/g, "");
              console.error(traceback);
              if (codeEl.tagName === "SPAN") {
                let newEl = document.createElement("code");
                newEl.textContent = "${" + code + "}";
                newEl.title = traceback;
                codeEl.replaceWith(newEl);
                codeEl = newEl;
              }
              codeEl.title = traceback;
              codeEl.style.color = "#900";
            } else {
              let newEl = document.createElement("span");
              newEl.className = "rendered_code";
              newEl.title = code;
              if (output.content.data["text/html"]) {
                newEl.innerHTML = output.content.data["text/html"];
              } else {
                newEl.textContent = output.content.data["text/plain"];
              }
              codeEl.replaceWith(newEl);
              codeEl = newEl;
            }
            if (totalTime > 1000) {
              codeEl.style.color = "#900";
              codeEl = `Time warning: ${Math.floor(totalTime / 1000)}` + (codeEl.title ? "\n" + codeEl.title : "");
            }
          }
        }
      };
      if (!cell.notebook.kernel) {
        console.warn("No kernel for", code);
        return;
      }
      console.log("Executing code", code);
      cell.notebook.kernel.execute(code, callbacks, {
        silent: false,
        store_history: false,
        stop_on_error: true,
      });
      }
  }

  return {
    load_ipython_extension
  };
});