I'v heard this question, and I'm unsure as how to solve it.
The requirement is: implement the function from so it will preform like so on the following scenario:
var x = from(3);
console.log(x()); //outputs 3
console.log(x()); //outputs 4
//TODO: implement from()
I tried something like:
function from(val) {
var counter = val;
return function(){
return counter+=1;
}
}
But the first time I run it, it increments the value, So that's a no go.
var x = from(3);
function from(startValue) {
var counter = startValue;
return function() {
return counter++;
}
}
console.log(x()); //outputs 3
console.log(x()); //outputs 4
The most straightforward solution would be to simply subtract 1 from counter:
function from(val) {
var counter = val - 1;
return function(){
return counter += 1;
}
}
However, in this case you can make use of the postfix ++ operator, because in counter++, the value of counter is increased by one, but the old value of counter is returned.
You should be good to go with
function from(val) {
var counter = val;
return function(){
return counter++;
}
}
For completeness, the equivalent to counter += 1 would be ++counter.
function from(val) {
var counter = val;
return function() {
return counter++;
}
}
var x = from(3);
alert(x()); //outputs 3
alert(x()); //outputs 4
alert(x()); //outputs 5
alert(x()); //outputs 6
alert(x()); //outputs 7
alert(x()); //outputs 8Try this
counter+=1returncounter++, that waycounteris first returned, then incremented.