Writing Scripts

The most basic MESA Script exports a class with a script() method. The code is executed in a V8 environment and can be written in standard Javascript or ES6. The class can contain additional methods or variables.

Parameters

During runtime, the script() method will be called and passed two parameters, payload and context.

The context parameter contains (read full details):

Name	Type	Description
payload	object	The payload data
shop	Shop	Complete Shopify shop object
shop.email	string	Merchant's email address
shop.myshopify_domain	string	Shop string. Example: myshop.myshopify.com
shop.myshopify_domain	domain	Shop's domain if it has been customized, otherwise the myshopify domain
steps	object	An object containing the full payload for each step run in this automation so far, keyed by each step's key. For example steps.shopify.
trigger	Trigger	The complete Trigger object contains information about the current step being run
task	Task	The complete Task object contains information about this specific task run
automation	Automation	The complete Automation object contains information about the workflow

Basic MESA Script

const Mesa = require('vendor/Mesa.js');

/**
 * A MESA Script exports a class with a script() method.
 */
module.exports = new class {

  /**
   * MESA Script
   *
   * @param {object} payload The payload data
   * @param {object} context Additional context about this task
   */
  script = (payload, context) => {
    const vars = context.steps;

    // Add your custom code here
    // Line items from a Shopify Order Created trigger would be available as something like `vars.shopify.line_items`

    // We're done, call the next step!
    Mesa.output.next(payload);
  }
}

MESA Scripts can call any of the MESA SDK methods or methods from our libraries.

Timezones

All system timezones are in your Shopify Store's timezone. You can view and update your timezone from the Shopify Dashboard: Admin > Settings > General, under "Standards and formats". If you need to get dates in a different timezone, use the Mesa.date.setTimezone(timezone) method.

Unsupported nodejs methods

Scripts are run in a stock V8 environment. This means that some common NodeJS methods are not available:

• request(): Alternative: Mesa.request.*() Documentation.

• console.log(): Alternative: Mesa.log.*() Documentation.

• DOM manipulation methods: Alternative: Mesa.xml.decode() Documentation.