drafts_zettelkasten.js

var zk_get_metadata = function(d, pattern) {
  let match = zk_metadata(d)
    .match(RegExp("^" + pattern + ": (.*)", 'm'));
  if (match !== null) {
    return match[1];
  } else {
    return null;
  }
};

var zk_update_metadata = function(d, pattern, value) {
  let metadata = zk_metadata(d);
  let body = zk_body(d);
  let lines = [];

  if (metadata == "") {
    lines = [`${pattern}: ${value}`];
  } else {
    lines = metadata.split("\n");
    let index = lines.findIndex((meta) => RegExp("^" + pattern + ": (.*)", '').test(meta));

    if (index == -1 ) {
      lines.push(`${pattern}: ${value}`);
    } else {
      lines[index] = `${pattern}: ${value}`;
    }
  }

  d.content = lines.join("\n") + "\n\n" + body;
  d.update();
};

var zk_add_tag = function(d, tag) {
  let tags = zk_get_metadata(d, "tags") || "";
  tags = tags.split(/, ?/).filter((a) => a != '');

  if (!tags.includes(tag)) {
    tags.push(tag);
  }

  zk_update_metadata(d, "tags", tags.join(", "));
};

var zk_extract_tags = function(d) {
  let matches = [...zk_body(d).matchAll(/#\w+/g)].map((m) => m[0]);

  for (t of matches) {
    zk_add_tag(d, t)
  }
}

var zk_title = function(d) {
  if (zk_get_metadata(d, "title") != null) {
    title = zk_get_metadata(d, "title");
  } else if (zk_body(d).split("\n")[0] != "") {
    title = zk_body(d).split("\n")[0];
  } else {
    title = ""
  }
  return title;
}

var zk_id = function(d) {
  if (d.content.search(/^id: (.*)/) != -1) {
    id = zk_get_metadata(draft, "id");
  }
  else {
    id = strftime(d.createdAt, "%Y%m%d%H%M%S").toString()
  }
  return id;
}

var zk_metadata = function(d) {
  if ((/^\w+: .*/).test(d.content)) {
    let lines = d.content.split("\n");
    let i = 0;

    // skip metadata
    while (/^\w+: .*/.test(lines[i])) {
      i++;
    }
    // skip blank lines
    while (/^\s*$/.test(lines[i])) {
      i++;
    }
    return lines.slice(0, i-1).join("\n");
  } else {
    return "";
  }
};

var zk_body = function(d) {
  if ((/^\w+: .*/).test(d.content)) {
    let lines = d.content.split("\n");
    let i = 0;
    // skip metadata
    while (/^\w+: .*/.test(lines[i])) {
      i++;
    }
    return lines.slice(i+1).join("\n");
  } else {
    return d.content;
  }
};