if陳述句滿足多個條件但在第一個匹配的條件處停止

我正在使用 if 陳述句并試圖確保它在滿足大多數條件時停止。例如，如果我有以下代碼：

  const determineLevel = () => {
    const wentToKindergarten = true;
    const wentToElementary = true;
    const wentToHighSchool = true;
    const wentToCollege = false;

    if (wentToKindergarten) {
      return 1;
    }

    if (wentToKindergarten && wentToElementary) {
      return 2;
    }

        if (wentToKindergarten && wentToElementary && wentToHighSchool) {
      return 3;
    }

 
     if (wentToKindergarten && wentToElementary && wentToHighSchool && wentToCollege) {
      return 4;
    }

    return;
  };

在這個例子中，如果一個學生上過幼兒園、小學和高中，但大學輟學了，我該如何實作？現在，它只是在它滿足的第一個條件處停止。謝謝！

uj5u.com熱心網友回復：

  const determineLevel = () => {
    const wentToKindergarten = true;
    const wentToElementary = true;
    const wentToHighSchool = true;
    const wentToCollege = false;
    var returnme=0;


    if (wentToKindergarten) {
      returnme= 1;
    }

    if (wentToKindergarten && wentToElementary) {
      returnme= 2;
    }

        if (wentToKindergarten && wentToElementary && wentToHighSchool) {
      returnme= 3;
    }

 
     if (wentToKindergarten && wentToElementary && wentToHighSchool && wentToCollege) {
      returnme= 4;
    }

    return returnme;
  };

編輯：或者您可能更喜歡以相反的順序放置條件，以便首先檢查最難滿足的條件。無論你喜歡什么。

uj5u.com熱心網友回復：

return 陳述句完成函式，函式將不會在它找到的第一個 return 陳述句之后執行。因此，撰寫代碼的更好方法是：

const determineLevel = () => {
    var returnNumber;
    const wentToKindergarten = true;
    const wentToElementary = true;
    const wentToHighSchool = true;
    const wentToCollege = false;

    if (wentToKindergarten) {
      returnNumber = 1;
    }

    if (wentToKindergarten && wentToElementary) {
      returnNumber = 2;
    }

        if (wentToKindergarten && wentToElementary && wentToHighSchool) {
      return = 3;
    }

 
     if (wentToKindergarten && wentToElementary && wentToHighSchool && wentToCollege) {
      returnNumber = 4;
    }

    if(returnNumber > 0)
    {
        return returnNumber;
    }
    return;
  };

通過這種方式，您可以檢查所有場景，然后在最后回傳您需要的任何數字。

uj5u.com熱心網友回復：

您的代碼不適用于您的邏輯，因為您在每個 if 條件檢查中回傳一個值，這將導致函式在第一個條件變為真后停止執行。

您可以將if條件更改為else-if條件。

或者你可以有一個變數來跟蹤，

const determineLevel = () => {
const wentToKindergarten = true;
const wentToElementary = true;
const wentToHighSchool = true;
const wentToCollege = false;
let condition;
if (wentToKindergarten) {
  condition= 1;
}

if (wentToKindergarten && wentToElementary) {
  condition= 2;
}

if (wentToKindergarten && wentToElementary && wentToHighSchool) {
  condition= 3;
}


 if (wentToKindergarten && wentToElementary && wentToHighSchool && wentToCollege) {
  condition= 4;
}

 return condition;
};

uj5u.com熱心網友回復：

1 - 以相反的順序。

if ( wentToKindergarten 
   && wentToElementary 
   && wentToHighSchool 
   && wentToCollege     )   return 4;

if (wentToKindergarten 
   && wentToElementary 
   && wentToHighSchool  )   return 3;

if ( wentToKindergarten 
   && wentToElementary  )   return 2;

if (wentToKindergarten  )   return 1;

2 - 與其他一些。

if (wentToKindergarten) 
  if (wentToKindergarten)
    if (wentToHighSchool)
      if (wentToCollege)  return 4
      else                return 3
    else                  return 2
  else                    return 1
else  return          

3 - 使用二進制表示：

let rep = 0b0000

if (wentToKindergarten) rep |= 0b0001
if (wentToElementary)   rep |= 0b0010
if (wentToHighSchool)   rep |= 0b0100
if (wentToCollege)      rep |= 0b1000

if ( rep |= 0b0001 ) return 1
if ( rep |= 0b0011 ) return 2
if ( rep |= 0b0111 ) return 3
if ( rep |= 0b1111 ) return 4

return

標籤：javascript if 语句 切换语句 布尔值 条件语句

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