The Run script block allows you to execute JavaScript code within your project. Below are its functionalities, limitations, and examples to guide proper usage.

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Key Features

  • The Script block enables you to execute JavaScript code, but it does not allow you to create custom visual blocks.
  • Variables in the script are evaluated, not parsed, so they must be treated as real JavaScript variables.

Note: Use console.log({{My variable}}) instead of console.log("{{My variable}}").

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setVariable Function

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Purpose

If you want to set a variable value with Javascript, the Set Variable is more appropriate for most cases. However setVariable function allows you to set values within a Script block.

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Example

if ({{My variable}} === 'foo') {
  setVariable('My variable', 'bar');
} else {
  setVariable('My variable', 'other');
}

Important:

  • The setVariable function is only available in scripts executed on the server.
  • It will not work if the Execute on client? option is checked.

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Server-Side Script Limitations

When scripts are executed on the server, they run in a secure, isolated environment. As a result, some JavaScript functionalities are restricted:

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Restricted Functions

  • Global functions like console.log, setTimeout, and setInterval are not available.
  • Importing external libraries using import or require is not supported.
  • Browser APIs like window, document, and localStorage are not accessible.

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Fetch Behavior

The behavior of the fetch function differs from the native implementation:

  • The response will always be a string, even if the server returns a JSON object.
  • You need to manually parse the response using JSON.parse().

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Examples:

// ❌ This throws an error
const response = await fetch('https://jsonplaceholder.mycode.com/todos/1');
const data = await response.text();

// ✅ Correct usage
const response = await fetch('https://jsonplaceholder.mycode.com/todos/1');
const data = JSON.parse(response);

Note: Avoid using await response.text() or await response.json().

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Client-Side Script Execution

If you need access to browser APIs, ensure the Execute on client? option is checked. This allows the script to run in the user’s browser.

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Examples:

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Reload Page

window.location.reload();

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Redirect Based on Variable Value

if ({{Category}} === 'qualified') {
  window.location.href = 'https://my-site.com';
}