javascript - 当字段为空时如何动态更改数组字段的值

Question

这是我编写的代码:

for (let i = 0; i < result.length; i++) {
    if (result[i].mkp == ' ') {
        //the first time that a empty field happen
        //the array position is filled with "FRANQUIAS"
        result[i].mkp = "FRANQUIAS";
    }
    if (result[i].mkp == ' ') {
        //the second time that a empty field happen
        //the array position is filled with "TELEVENDAS"
        result[i].mkp = "TELEVENDAS";
    }
    if (result[i].mkp == ' ') {
        //the third time that a empty field happen
        //the array position is filled with "OCC"
        result[i].mkp = "OCC";
    }
}

但是我自己想不通如何才能达到将空字段更改为这三个字段的目的。有人可以帮助我吗？

Answer 1

保留一个额外的计数器变量，当出现空字段时该变量会递增。

// variable for keeping track of empty field
let c = 0;

for (let i = 0; i < result.length; i++) {
    // chek value or couter in addition to your condition
    if (c === 0 && result[i].mkp == ' ') {
        //the first time that a empty field happen
        //the array position is filled with "FRANQUIAS"
        result[i].mkp = "FRANQUIAS";
        // increment counter value whenever empty field occurs
        c++;
    }
    else if (c === 1 && result[i].mkp == ' ') {
        //the second time that a empty field happen
        //the array position is filled with "TELEVENDAS"
        result[i].mkp = "TELEVENDAS";
        c++;
    }
    else if (c === 2 && result[i].mkp == ' ') {
        //the third time that a empty field happen
        //the array position is filled with "OCC"
        result[i].mkp = "OCC";
        c++;
    }
}

---

您甚至可以通过使用包含这些值的数组来简化代码。

// variable for keeping track of empty field
let c = 0;
// array which contains the value
const val = [ 'FRANQUIAS', 'TELEVENDAS', 'OCC'];

for (let i = 0; i < result.length; i++) {
     // check counter is less than 3(update if there is more possibility or use c < val.length)
     // and check value is empty
     if (c < 3 && result[i].mkp == ' ') {
        // update value with corresponding value in array 
        // and increment, where `c++` returns current value and increments 
        result[i].mkp = val[c++];
    }
}