Questions are as follows：
The first time you call the add, it will return 1;
the second time you call, it returns 2;
Can only be written in function
var add = function () {
// start only
// end
};
console.log(add()); // 1
console.log(add()); // 2
The current idea is that a global variable is needed
So the current way of writing
But this way of writing does not meet the requirements
var add = (function () {
let counter=0
return function () {
counter += 1; return counter;}
}();
I don't know how to adjust the code to solve this question thank you
somethig like this?
var add = {
time: 0,
call: () => {
add.time++;
console.log(add.time);
}
};
add.call(); // 1
add.call(); // 2I'd do it like this. It implicitely creates a global variable, which is dirty as hell, but it meets the (strange) requirements.
var add = function () {
if(typeof a === "undefined") a = 0;
return ++a;
};
console.log(add()); // 1
console.log(add()); // 2All the solutions that came to mind:
Use a property assigned to the function
// in JS, a function is also an object; you can assign properties to it.
function add() {
if (add.value === undefined) add.value = 0;
return ++add.value;
}
console.log(add());
console.log(add());Create a local scope
var add = (function() {
var value = 0;
return function() {
return ++value;
};
})();
console.log(add());
console.log(add());Use the global scope
function add() {
if (window._currentValue === undefined) window._currentValue = 0;
return ++window._currentValue;
}
console.log(add());
console.log(add());I think that the first solution may be of particular interest to you.