如何基于分组大小数组批量分组数组元素？兼容ECMA5实现

需要基于给定的group_size数组对元素数组进行分组：先按group_size的元素依次分割，剩余元素按group_size中的最大值分组。现有代码未得到预期结果：

现有代码 #

var group_size = [1, 3, 5];
var elements = ['a','b','c','d','e','f','g','h','i','j','k','l'];
        
var output = [];
for (var i=0; i < group_size.length; i++) {
    output.push(elements.slice(i, group_size[i]))
}
console.log(output);

当前输出 #

[["a"], ["b", "c"], ["c", "d", "e"]]

预期输出 #

[['a'], ['b','c','d'],['e','f','g','h','i'],['j','k','l']]

分组规则 #

• 优先按group_size数组中的元素依次分组
• 完成group_size的所有分组后，剩余元素按group_size的最大值进行分组（最后一组不足最大值则保留剩余元素）
• 示例：

// 示例1
Input = ['a','b','c']
Output = [['a'], ['b','c']]

// 示例2
Input = ['a','b','c','d','e']
Output = [['a'], ['b','c','d'], ['e']]

// 示例3
Input = ['a','b','c','d','e','f','g','h','i','j','k','l']
Output = [['a'], ['b','c','d'],['e','f','g','h','i'],['j','k','l']]

// 示例4
Input = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p']
Output = [['a'], ['b','c','d'],['e','f','g','h','i'],['j','k','l','m','n'], ['o','p']]

ECMA5兼容解决方案 #

function groupElements(groupSize, elements) {
    var output = [];
    var currentIndex = 0;
    var maxGroupSize = 0;
    
    // 找出groupSize中的最大值
    for (var i = 0; i < groupSize.length; i++) {
        if (groupSize[i] > maxGroupSize) {
            maxGroupSize = groupSize[i];
        }
    }
    
    // 按groupSize依次分组
    for (var j = 0; j < groupSize.length; j++) {
        if (currentIndex >= elements.length) break;
        var endIndex = currentIndex + groupSize[j];
        output.push(elements.slice(currentIndex, endIndex));
        currentIndex = endIndex;
    }
    
    // 处理剩余元素，按最大分组大小分割
    while (currentIndex < elements.length) {
        var endIndex = currentIndex + maxGroupSize;
        output.push(elements.slice(currentIndex, endIndex));
        currentIndex = endIndex;
    }
    
    return output;
}

// 测试示例
var group_size = [1, 3, 5];
var elements1 = ['a','b','c','d','e','f','g','h','i','j','k','l'];
console.log(groupElements(group_size, elements1)); 
// 输出：[['a'], ['b','c','d'],['e','f','g','h','i'],['j','k','l']]

var elements2 = ['a','b','c'];
console.log(groupElements(group_size, elements2)); 
// 输出：[['a'], ['b','c']]

var elements3 = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p'];
console.log(groupElements(group_size, elements3)); 
// 输出：[['a'], ['b','c','d'],['e','f','g','h','i'],['j','k','l','m','n'], ['o','p']]

代码说明 #

1. 计算最大分组长度：遍历groupSize数组记录最大值，用于后续剩余元素的分组
2. 按指定规则分组：维护currentIndex作为当前分割的起始位置，每次从该位置取对应长度的元素并更新起始位置
3. 处理剩余元素：当currentIndex未到达数组末尾时，循环按最大长度分割剩余元素，直到处理完成

内容的提问来源于stack exchange，提问作者Learner