7 ms·

The variable declaration is hoisted to the top, then is assigned a named function expression `func` so that `func.name === 'func'`. Useful for proper error me

The variable declaration is hoisted to the top, then is assigned a named function expression `func` so that `func.name === 'func'`. Useful for proper error messages and stack traces. Something else I'm missing?

thomaslangston 13y ago
Could you go into more detail about why you would do A) var func = function func() { /* blah */ }; Instead of B) function func() { /* blah */ };
- yuchi 13y ago
  var func = _.memoize(function private_non_memoized_func() { func(); // "light" private_non_memoized_func(); // "heavy" });
- ShellfishMeme 13y ago
  Let's say you want to define a function to be used for a certain operation on two numbers dependent on some boolean. if (addition) { // operation = add } else { // operation = subtract } If you use function declarations you might run into bugs if (addition) { function operation (a, b) { return a + b; } } else { function operation (a, b) { return a - b; } } console.log(operation(1,2)); Here it might happen that you don't get the expected function. Additionally it's much less clear what's going on. Compare it to this: var operation; if (addition) { operation = function add (a, b) { return a + b; }; } else { operation = function subtract (a, b) { return a - b; }; } console.log(operation(1, 2)); Here it's very obvious what's going on and your operation function has a name that reflects what it does. Personally I prever never to rely on function hoisting and always declare functions using function expressions. It keeps the code style more consistent and it's clearer what is happening in your program.
- deleted 13y ago
  [deleted]
solox3 13y ago
Yeah, the average applicant says something along those lines. The top applicants also mention the IE bug associated with named function expressions: http://kangax.github.io/nfe/ http://kangax.github.io/nfe/
3minus1 13y ago
Don't forget that the second func is unnecessary, unless it's a function that calls itself. Also it will show up as func when debugging instead of anonymous function.

thomaslangston 13y ago

Could you go into more detail about why you would do A) var func = function func() { /* blah */ }; Instead of B) function func() { /* blah */ };

yuchi 13y ago
var func = _.memoize(function private_non_memoized_func() { func(); // "light" private_non_memoized_func(); // "heavy" });
ShellfishMeme 13y ago
Let's say you want to define a function to be used for a certain operation on two numbers dependent on some boolean. if (addition) { // operation = add } else { // operation = subtract } If you use function declarations you might run into bugs if (addition) { function operation (a, b) { return a + b; } } else { function operation (a, b) { return a - b; } } console.log(operation(1,2)); Here it might happen that you don't get the expected function. Additionally it's much less clear what's going on. Compare it to this: var operation; if (addition) { operation = function add (a, b) { return a + b; }; } else { operation = function subtract (a, b) { return a - b; }; } console.log(operation(1, 2)); Here it's very obvious what's going on and your operation function has a name that reflects what it does. Personally I prever never to rely on function hoisting and always declare functions using function expressions. It keeps the code style more consistent and it's clearer what is happening in your program.
deleted 13y ago
[deleted]

solox3 13y ago

Yeah, the average applicant says something along those lines. The top applicants also mention the IE bug associated with named function expressions: http://kangax.github.io/nfe/ http://kangax.github.io/nfe/

3minus1 13y ago

Don't forget that the second func is unnecessary, unless it's a function that calls itself. Also it will show up as func when debugging instead of anonymous function.