onerror()

onerror(msg) is supported only by JavaScript (including TypeScript) strategies. It is called when main() ends with an uncaught exception; the argument msg is the error message. When onerror() is called, onexit() is not. It may run for at most 5 minutes and is terminated when it exceeds that. The backtesting system does not support this function.

Python and Rust strategies do not support onerror().

Examples

    javascript
    
    
function main() {
    var arr = []
    Log(arr[6].Close)  // deliberately raise an exception here
}

function onerror(msg) {
    Log("Error:", msg)
}

    python
    
    
# Not supported in Python

    rust
    
    
// Not supported in Rust