Javascript 有没有一种方法可以将reduce应用于两个数组,但不重置调用之间的累加器?
因此,如果我有一个对象数组:Javascript 有没有一种方法可以将reduce应用于两个数组,但不重置调用之间的累加器?,javascript,arrays,performance,Javascript,Arrays,Performance,因此,如果我有一个对象数组: var synched = [{ name = "something", value = 11132 }, { name = "something else", value = 1231233 }...] 另一个数组几乎相同,但包含一些其他值: var opened = [{ name = "something", value = 1233312 }, { name = "something else", value
var synched = [{
name = "something",
value = 11132
}, {
name = "something else",
value = 1231233
}...]
另一个数组几乎相同,但包含一些其他值:
var opened = [{
name = "something",
value = 1233312
}, {
name = "something else",
value = 12312333
}, {
name = "something",
value = 1241233
}]
我想把它们全部合并到一个对象数组中,在这个数组中我计算每个数组中“name”的准确度
var result = [{
name: "something",
opened: 2,
synched: 1,
total: 3
}, {
name: "something else",
opened: 1,
synched: 1,
total: 2
}]
有没有比多个array.reduce
调用更有效的方法
var data = synched.reduce(function (data, item) {
var key = item.name
var created = (data[key] || (data[key] = {'name': key, 'opened': 0, 'synched': 0, 'total': 0}));
created['synched'] += 1;
created['total'] += 1;
return data;
}, {});
var data1 = opened.reduce(function (data1, item) {
var key = item.name
var created = (data1[key] || (data1[key] = {'name': key, 'opened': 0, 'synched': 0, 'total': 0}));
created['opened'] += 1;
created['total'] += 1;
return data1;
}, {});
Object.keys(data).forEach(function (key) {
if(data1.hasOwnProperty(key)){
data1[key]['synched'] = data[key]['synched'];
data1[key]['total'] = data[key]['total'] + data1[key]['total'];
} else {
data1[key] = data[key];
}
});
var result = Object.keys(data1).map(function(item) { return data1[item]; });
编辑:
以下@Pointy建议我可以做到这一点:
var data1 = opened.reduce(function (data, item) {
var key = item.name
var created = (data[key] || (data[key] = {'name': key, 'opened': 0, 'synched': 0, 'total': 0}));
created['opened'] += 1;
created['total'] += 1;
return data;
}, data);
这将允许我摆脱第三次迭代。谢谢 只需将
数据
作为累加器参数传递给第二个.reduce()
?啊!知道了!这是初始值。我需要将数据
作为累加器传入,但也要作为初始值,而不是{}
。这就是为什么它只是重置我的数据输出。我现在明白了。谢谢