使用对象属性作为 "delimiter" 的对象数组块

Question

给定以下数组：

var arr = [{id:1 , code:0},
           {id:1 , code:12},
           {id:1 , code:0},
           {id:1 , code:0},
           {id:1 , code:5}];

如何使用 lodash，每次 code 不等于 0 时拆分数组并得到以下结果？

[
 [{id:1 , code:0},{id:1 , code:12}],
 [{id:1 , code:0},{id:1 , code:0},{id:1 , code:5}]
]

Answer 1

你可以使用 Array.prototype.reduce（或 lodash 的 _.reduce()）：

var arr = [{id:1 , code:0},
           {id:1 , code:12},
           {id:1 , code:0},
           {id:1 , code:0},
           {id:1 , code:5}];

var result = arr.reduce(function(result, item, index, arr) {
  index || result.push([]); // if 1st item add sub array
  
  result[result.length - 1].push(item); // add current item to last sub array
  
  item.code !== 0 && index < arr.length - 1 && result.push([]); // if the current item code is not 0, and it's not the last item in the original array, add another sub array
  
  return result;
}, []);

console.log(result);

Answer 2

另一种 "native" JS 解决方案使用 Array.splice 函数：

var arr = [{id:1 , code:0},{id:1 , code:12}, {id:1 , code:0},{id:1 , code:0}, {id:1 , code:5}],
    chunks = [];

for (var i = 0; i < arr.length; i++) {
    arr[i].code !== 0 && chunks.push(arr.splice(0, i + 1));
}

console.log(JSON.stringify(chunks, 0, 4));

Answer 3

一个简单的 Javascript 解决方案，只有一个循环而不改变原始数组。

var arr = [{ id: 1, code: 0 }, { id: 1, code: 12 }, { id: 1, code: 0 }, { id: 1, code: 0 }, { id: 1, code: 5 }],
    grouped = arr.reduce(function (r, a, i) {
        var l = r[r.length - 1];
        if (!i || l[l.length - 1].code) {
            r.push([a]);
        } else {
            l.push(a);
        }
        return r;
    }, []);

console.log(grouped)

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Answer 4

结果是，如果您希望减少元素数量，那么我想您只需要减少即可。

var arr = [{id:1 , code:0},
           {id:1 , code:12},
           {id:1 , code:0},
           {id:1 , code:0},
           {id:1 , code:5}],
reduced = arr.reduce((red,obj) => !obj.code ? red[red.length-1].length === 1 ||
                                              red[red.length-1].length === 0 ? (red[red.length-1].push(obj),red)
                                                                             : red.concat([[obj]])
                                            : (red[red.length-1].push(obj),red),[[]]);
console.log(reduced);

使用对象属性作为 "delimiter" 的对象数组块

Chunks of an Array of objects using an object property as the "delimiter"

javascript

arrays

chunks

web

lodash

使用对象 属性 作为 "delimiter" 的对象数组块

Chunks of an Array of objects using an object property as the "delimiter"

javascript

arrays

chunks

web

lodash

使用对象属性作为 "delimiter" 的对象数组块