在函数之间共享Javascript变量

Question

So I have a few variables that I need to use within two separate functions. The first function essentially uses the variables to calculate and then display something (a conjugated verb). The second function uses the variables to see if the user's answers were correct, and changes some HTML styling accordingly.

However, these variables are calculated randomly, like this:

function randomIntFromInterval(min,max) {
return Math.floor(Math.random()*(max-min+1)+min); }

var tense = randomIntFromInterval(1, 6);
var person = randomIntFromInterval(1, 3);
var number = randomIntFromInterval(1, 2);
var voice = randomIntFromInterval(1, 2);

I can't declare them as global variables outside a function, because they need to be recalculated every time the first function is called. I can't declare them in their own function and call it inside the original two functions, because both of the functions needs the same values.

How can I do this?

Answer 1

I think you're asking how to pass a structure of values between two functions. What you (probably) don't want to do is pass each one individually, although that is an option if you only have a few and they come from different sources. If they come from the same, or similar, sources then you can use an object with named keys like:

function randomIntFromInterval(min,max) {
  return Math.floor(Math.random()*(max-min+1)+min); 
}

function getRandomSections() {
  return {
    tense: randomIntFromInterval(1, 6),
    person: randomIntFromInterval(1, 3),
    number: randomIntFromInterval(1, 2),
    voice: randomIntFromInterval(1, 2)
  };
}

function doSomethingWithSections(sections) {
  // do some things
}

function doSomethingElseWithSections(sections) {
  // do some things
}

// Put it all together
var sections = getRandomSections();
doSomethingWithSections(sections);
doSomethingElseWithSections(sections); // using the same values in a second function

If they came from unrelated places, I would suggest using individual params (as suggested by @jfriend00 in the comments) and doing:

function doSomethingWith(tense, person, number, voice) {
  // do some things
}

doSomethingWithSections(getTense(), getPerson(), getNumber(), getVoice());

If you want to make the list of fields somewhat dynamic, you can make getRandomSections data-driven like:

function getSections(names, cb) {
  var obj = {};
  names.forEach(function (name) {
    obj[name] = cb(x, y);
  });
  return obj;
}

// Used as
getSections(['tense', 'person', 'number', 'voice'], randomIntFromInterval);

Answer 2

Cant you do something like this-

function randomIntFromInterval(min,max) {
    return Math.floor(Math.random()*(max-min+1)+min); 
}

function f1(t, p, n, v){ //arguments for function
    //something
}
function f2(t, p, n, v){
    //something
}

function main(){
    var tense = randomIntFromInterval(1, 6);
    var person = randomIntFromInterval(1, 3);
    var number = randomIntFromInterval(1, 2);
    var voice = randomIntFromInterval(1, 2);

    f1(tense, person, number, voice);
    f2(tense, person, number, voice);
}

main();