为 IF ELSE IF 语句返回一个函数

Question

I am trying to run a block of code that is series of IF ELSE IF statements, that checks to see if certain conditions are true.

    if (2 > 1) {
        return true;
    }

    else if (3 > 1) {
        return true;
    }

    else if (4 > 1) {
        return true;
    }

    else {
        alert('Not all conditions are true')
    }

It is working fine, but I want to add a function at the end, if all the conditions are true, In the code below I added the function, but now it seems to run the function without checking all the conditions first

    if (2 > 1) {
        return true;
    }
    else if (3 > 1) {
        return true;
    }
    else if (4 > 1) {
        return true;
    }
    else {
        alert('Not all conditions are true')
    }

    // Run this function after checking all the conditions are true
    allConditionsTrue();

I think I am getting confused with where the function should be placed.

Any help is greatly appreciated :)

Answer 1

For an arbitrary count of condition and with an immediate exit if one previous condition is false and the next is true , you could take a variable for the state if someFalse value occurs.

Afetr checkin all conditions check someFalse and return with 'Not all conditions are true' .

Finally it is clear, that all conditions are true and you can call a function for this case.

 function check(value) { function allConditionsTrue() { console.log('All conditions are true'); } let someFalse = false, conditions = [value < 2, value < 3, value < 4], fn = c => c ? someFalse : !(someFalse = true); if (conditions.some(fn)) return true; if (someFalse) { console.log('Not all conditions are true'); return false; } allConditionsTrue(); return true; } console.log(1, check(1)); console.log(2, check(2)); console.log(3, check(3)); console.log(4, check(4));

Answer 2

Take a look at && (AND) and || (OR) operators:

 if (2>1 && 3>1 && 4>1) {  
      allConditionsTrue(); 
      return true; 
   } else { 
     alert('not all conditions true'); 
   }

Answer 3

You placed the function call outside of all the checks so it is independent of the conditions. You can give it its own if block like:

if (2 > 1 && 3 > 1 && 4 > 1) {
  allConditionsTrue()
}

Or if you don't want to rewrite all the checks then you can create an array to hold their respective values like

let conds = [false, false, false]
if (2 > 1) {
    conds[0] = true
}
if (3 > 1) {
    conds[1] = true
}
if (4 > 1) {
    conds[2] = true
}
if (!conds.some(v => !v)) { // all are true
    allConditionsTrue()
}
if (conds.some(v => v)) {
    return true
} else {
    alert('Not all conditions are true')
}

Edit: corrected with suggestion from comment

Edit 2: an improvement