Function boa::builtins::string::substr

pub fn substr(
    this: &mut Value, 
    args: &[Value], 
    ctx: &mut Interpreter
) -> ResultValue

String.prototype.substr( start[, length] )

The substr() method returns a portion of the string, starting at the specified index and extending for a given number of characters afterward.

More information:

• ECMAScript reference
• MDN documentation

https://tc39.es/ecma262/#sec-string.prototype.substr