javascript - 在 JavaScript 中创建对象数组的所有组合

Question

我想找到 n 数组的选项属性的所有组合。在示例中，数组的长度为 3，但该函数也应该适用于更大或更小的数组大小。

var arr = [{
    name: 'Fruit',
    options: ['apple', 'kiwi']
}, {
    name: 'Food',
    options: ['bread', 'rice']
}, {
    name: 'Drink',
    options: ['water', 'cola']
}]

结果应打印以下语句

Fruit: apple | Food: bread | Drink: water
Fruit: apple | Food: bread | Drink: cola
Fruit: apple | Food: rice | Drink: water
Fruit: apple | Food: rice | Drink: cola
Fruit: kiwi | Food: bread | Drink: water
Fruit: kiwi | Food: bread | Drink: cola
Fruit: kiwi | Food: rice | Drink: water
Fruit: kiwi | Food: rice | Drink: cola

我已阅读此答案Finding All Combinations (Cartesian product) of JavaScript array values，但在我的示例中，数组是一个对象，我无法弄清楚如何获取属性。这是我到目前为止所拥有的：

function allPossibleCases(arr) {
    if (arr.length === 0) {
        return [];
    } else if (arr.length ===1){
        return arr[0].options;
    } else {
        var result = [];
        var allCasesOfRest = allPossibleCases(arr.slice(1));  // recur with the rest of array
        for (var c in allCasesOfRest) {
            for (var i = 0; i < arr[0].options.length; i++) {
                console.log(arr[0].name, ": ", arr[0].options[i], "| ", allCasesOfRest[c])
            }
        }
        return result;
    }
}

输出是：

Food :  bread |  water
Food :  rice |  water
Food :  bread |  cola
Food :  rice |  cola

我错过了什么？

标签： javascript

Answer 1

您可以获取值、构建笛卡尔积并映射属性。

var array = [{ name: 'Fruit', options: ['apple', 'kiwi'] }, { name: 'Food', options: ['bread', 'rice'] }, { name: 'Drink', options: ['water', 'cola'] }],
    keys = array.map(({ name }) => name),
    result = array
        .map(({ options }) => options)
        .reduce((a, b) => a.reduce((r, v) => r.concat(b.map(w => [].concat(v, w))), []))
        .map(a => Object.assign(...keys.map((k, i) => ({ [k]: a[i] }))));
	
console.log(result);

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