Error Reference

This page describes all runtime errors you may encounter when writing dxScript indicators, along with explanations and solutions.

Member Access Errors

Not a function

Occurs when you try to invoke a non-callable value as a function.

Common Causes

• Calling a property that is not a method
• Calling a built-in series (like close, open) as a function

Example

// ❌ Wrong: 'close' is a series, not a function
const x = close();

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'module' has no member 'X'

Occurs when accessing a non-existent member of a module or object.

Common Causes

• Typo in method or property name
• Accessing removed or renamed API

Example

// ❌ Wrong: Typo in method name
const avg = color.GREN;
// Error: 'color' has no member 'GREN'. Did you mean 'color.GREEN'?

// ❌ Wrong: Typo in method name
const len = input.bol("bool", true);
// Error: 'input' has no member 'bol'. Did you mean 'input.bool'?

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'module.X' is read-only and cannot be modified

Occurs when trying to assign a value to a read-only property.

Common Causes

• Trying to modify module objects

Example

// ❌ Wrong: Cannot modify module
input.bool = function () {
};
// Error: 'input.bool' is read-only and cannot be modified

Argument Errors

'method' expected at least N argument(s), got M

Occurs when a function receives fewer arguments than required.

Common Causes

• Missing required parameters
• Optional parameters placed before required ones
• Forgetting to pass options object

Example

// ❌ Wrong: Missing name parameter
input.bool(true);
// Error: 'input.bool' expected at least 2 argument(s), got 1

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'method' parameter 'name' must be T, got T'

Occurs when an argument has the wrong type.

Common Causes

• Passing a string where a number is expected
• Passing a number where a series is expected
• Passing the wrong object type

Example

// ❌ Wrong: String instead of number
const len = input.double("length", "20");
// Error: 'input.double' parameter 'argument 2' must be number, got string

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Troubleshooting Checklist

When you encounter an error:

1. Check the spelling: error messages often suggest the correct name
2. Verify the module: make sure you're using the right module (e.g., ta.sma not ts.sma)
3. Count arguments: check required vs optional parameters in reference
4. Check types: ensure arguments match expected types (number, string, series, etc.)
5. Check context: some functions only work in init section, others in onTick()
6. Check mutability: built-in series and modules are read-only