Google Apps Script:
Working with YAML

How to:

While Google Apps Script (GAS) doesn’t natively support YAML parsing or serialization, you can manipulate YAML data by using JavaScript libraries or writing custom parsing functions. For demonstration, let’s consider how to parse a YAML string using a custom function, since external libraries cannot be directly imported into GAS.

Assume you have a simple YAML configuration:

title: YAML Example
description: An example of how to handle YAML in Google Apps Script
tags:
  - Google Apps Script
  - YAML
  - Configuration

To parse this in Google Apps Script, use JavaScript’s string manipulation capabilities:

function parseYAML(yamlString) {
  var result = {};
  var lines = yamlString.split("\n");
  for (var i = 0; i < lines.length; i++) {
    var line = lines[i];
    if (line.includes(":")) {
      var parts = line.split(":");
      var key = parts[0].trim();
      var value = parts[1].trim();
      // Basic handling for arrays
      if (value.startsWith("-")) {
        value = [value.substring(1).trim()];
        while (i + 1 < lines.length && lines[i + 1].trim().startsWith("-")) {
          i++;
          value.push(lines[i].trim().substring(1).trim());
        }
      }
      result[key] = value;
    }
  }
  return result;
}

function testYamlParsing() {
  var yaml = "title: YAML Example\ndescription: An example of how to handle YAML in Google Apps Script\ntags:\n  - Google Apps Script\n  - YAML\n  - Configuration";
  var parsed = parseYAML(yaml);
  Logger.log(parsed);
}

When testYamlParsing() is executed, it outputs:

{ title: 'YAML Example',
  description: 'An example of how to handle YAML in Google Apps Script',
  tags: [ 'Google Apps Script', ' YAML', ' Configuration' ] }

This custom parsing approach is quite basic and may need adjustments to accommodate complex YAML files.

Deep Dive

YAML, initially released in 2001, aimed to be more human-readable than its predecessors like XML or JSON. While its simplicity and ease of use are widely appreciated, handling YAML in Google Apps Script presents challenges due to the lack of direct support. Consequently, programmers often rely on JavaScript’s versatility to parse and generate YAML data. However, for complex use cases, especially those involving deep nesting and advanced data structures, this method can get cumbersome and error-prone.

JSON, by contrast, is natively supported in Google Apps Script and most other programming environments, offering a more straightforward approach for data serialization and deserialization without additional parsing overhead. JSON’s syntax is less verbose than YAML’s, making it more suitable for data interchange in web applications. Nonetheless, YAML remains popular for configuration files and situations where human readability is paramount.

When working with YAML in Google Apps Script, consider the trade-offs between readability and ease of use. For comprehensive YAML manipulation, it may be worth exploring external tools or services that can convert YAML to JSON before processing it within your script.