function ( arg ) {
// any number of statements
return arg/2;
}
(note pattern!)
var halve = function ( arg ) {
return arg/2;
}
x = halve(256);
Define & Name
Use
(note pattern!)
Naming Functions
Using named functions
var cook = function(stuff, temperature, minutes){
var timer = 0;
while (timer < minutes) {
stuff = stuff + heat;
timer = timer+1;
}
return stuff;
}
var cake = cook(batter, 200, 30);
Define
Use
var timer=0;
var foo = function(arg){
{
var done = false;
console.log('done is ' + done);
}
console.log('done is ' + done);
console.log('timer is ' + timer);
}
console.log('done is ' + done);
SCOPE
Variables declared with var have "function scope"
Even buried in a block, vars can be seen throughout the whole function.
var timer=0;
var foo = function(arg){
{
let done = false;
console.log('done is ' + done);
}
console.log('done is ' + done);
console.log('timer is ' + timer);
}
console.log('done is ' + done);
SCOPE
Variables declared with let and const have "block scope"
Buried in a block, lets and consts can ONLY be seen within the block they are defined in.
