_js

The _js operator enables the use of custom JavaScript logic within Lowdefy configuration where operators are evaluated. The purpose of this operator is to facilitate quick implementation of fast, synchronous functions. Like other operators, these functions are evaluated during page render, thus slow functions can impact app performance. For more advanced logic, or when the use of external dependencies is necessary, instead develop a custom plugin.

Using Lowdefy operators in JavaScript

Certain Lowdefy operators can be used inside of the JavaScript function block. These operators are available as functions and will take their standard arguments.

Client JavaScript function prototype:

Function parameters passed to the operator method.

function ({ actions, event, input, location, lowdefyGlobal, request, state, urlQuery, user }) {
  // Your JavaScript code here
};

The function arguments available to the JavaScript function are:

• actions: function: Implements the _actions operator.
• event: function: Implements the _event operator.
• input: function: Implements the _input operator.
• location: function: Implements the _location operator.
• lowdefyGlobal: function: Implements the _global operator.
• request: function: Implements the _request operator.
• state: function: Implements the _state operator.
• urlQuery: function: Implements the _url_query operator.
• user: function: Implements the _user operator.

Server JavaScript function prototype:

Function parameters passed to the operator method.

function ({ payload, secrets, user }) {
  // Your JavaScript code here
};

The function arguments available to the JavaScript function are

• payload: function: Implements the _payload operator.
• secrets: function: Implements the _secret operator.
• user: function: Implements the _user operator.

string

The JavaScript function body, including the function return statement, excluding the function prototype.

Perform a calculation:

_js: |
  let x = state('input_1');
  let y = state('input_2');
  return x + y;

Create custom logic based on data from a request:

_js: |
  const products = request('get_products').data?.products ?? [];
  const laptopsWithRatingGreaterThan4 = products.filter(product =>
      product.category === "laptops" && product.rating > 4
  );
  if (laptopsWithRatingGreaterThan4.length > 3) {
      return true;
  }
  return false;

Chain array methods on request data:

_js: |
  const products = request('get_products').data?.products ?? [];
  const totalPriceOfPhones = products
      .filter(product => product.category === "smartphones")
      .reduce((acc, product) => acc + product.price, 0);
  return totalPriceOfPhones;