Execute JavaScript Code

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How it works

let age = {{user_age}};
let firstName = "{{first_name}}";

• For numbers, you can assign the value directly, such as let age = {{user_age}};.
• For text, place the value inside quotation marks, such as let name = "{{first_name}}";.
• Your code must include return to send a result back to the Flow.
• Select an Output Custom Field when you want to save the result for another step.

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Add the Action to a Flow

1

Open the Flow

Go to Flows, open the Flow you want to edit, then create or select a Perform Action node.

2

Select Execute JavaScript Code

In the Action menu, select Tools, then select Execute JavaScript Code.

3

Enter the JavaScript code

Enter your code in JavaScript code. Make sure the code ends with return.

4

Save the result

Under Output Custom Field, select the field that will receive the result, then click Save.

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Practical examples

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Calculate the final amount after a discount

let total = {{order_total}};
let discount = {{discount_percent}};

return Math.round(total - total * discount / 100);

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Calculate a delivery fee by area

let province = "{{province}}".trim().toLowerCase();
let total = {{order_total}};

if (total >= 500000) return 0;

let innerCity = ["hà nội", "ha noi", "hồ chí minh", "ho chi minh"];
return innerCity.includes(province) ? 30000 : 45000;

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Classify a customer

let totalSpent = {{total_spent}};

return totalSpent >= 1000000 ? "vip" : "standard";

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Validate an email address

let email = "{{email}}".trim();
let isValid = /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email);

return isValid ? "valid" : "invalid";

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Read an order amount from JSON

let jsonText = `{{order_json}}`;

try {
  let order = JSON.parse(jsonText);
  return Number(order.total || 0);
} catch (error) {
  return 0;
}

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Use the result in a Flow

• Insert the field in a message, such as Your total is {{final_total}}.
• Use a Condition node to create branches based on the result.
• Pass the result to another Action for further calculations or data updates.

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Tips for writing code

• Check that every field name inside {{...}} is correct.
• Put text values inside quotation marks, but leave numbers unquoted when you need to calculate with them directly.
• Always include a return statement.
• For JSON or potentially invalid data, use try...catch and return a fallback value.
• Test the Flow with a test contact before using it with customers.