Code Fellows Reading Notes

310

Understanding the JavaScript Call Stack

• What is a ‘call’?
  Function invocation

• How many ‘calls’ can happen at once?
  The call stack is synchronous, one call happens at once.

• What does LIFO mean?
  Last In, First Out; the last function pushed into the stack is the first to be popped out, when the function returns.

• Draw an example of a call stack and the functions that would need to be invoked to generate that call stack.
  

• What causes a Stack Overflow?
  When a recursive function without an exit point is invoked, a stack overflow will occur once the hosting environment maximum call size is exceeded.

JavaScript error messages

• What is a ‘reference error’?
  Attempting to use a variable that hasn’t been declared yet.

• What is a ‘syntax error’?
  This occurs when you have something that can’t be parsed in terms of syntax.

• What is a ‘range error’?
  Trying to manipulate an object with some kind of length and giving it an invalid length.

• What is a ‘type error’?
  The types you are trying to use or access are incompatible.

• What is a breakpoint?
  Allows you to stop execution of your code at a specified point and view the output to evaluate what is happening.

• What does the word ‘debugger’ do in your code?
  The debugger statement stops the execution of JavaScript, and calls the debugger.