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[英]How to get two arrays by mapping a predicate over an input array with Ramda
[英]Ramda to loop over array
循环可能是错误的术语,但它描述了我的尝试。 我想为平面数据提供结构,但是我还需要跟踪它来自的数组。
基本上我的规则是(每个数组):
如果存在1级,请给它提供项目name
和一个typechild
数组。 每次出现1级(即使在同一阵列中)时,也应创建一个新条目。
在typechild
,放置级别> 1的所有项目
如果不存在1级,请给它提供项目name
和一个typechild
数组。
我下面的代码几乎存在,不同之处在于它每次在看到第1级时都应创建一个数组。我的示例将有意义:
输入数据
[
{
"title": "Test 1",
"type": [{
"name": "Animal",
"level": 1
},
{
"name": "Food",
"level": 1
},
{
"name": "Chicken",
"level": 3
}
]
},
{
"title": "Test 2",
"type": [{
"name": "Foo",
"level": 2
}]
}
]
注意:动物和食物均为1级物品。 所以它应该像这样创建两个数组...
所需的输出
[
{
name: "Animal",
typechild: [
{
level: 2,
name: "Chicken"
}
]
},
{
name: "Food",
typechild: [
{
level: 2,
name: "Chicken"
}
]
},
{
name: "NoName",
typechild: [
{
level: 2,
name: "Foo"
}
]
}
]
拉姆达尝试(尝试在这里: https : //dpaste.de/JQHw ):
const levelEq = (n) => pipe(prop('level'), equals(n));
const topLevel = pipe(prop('type'), find(levelEq(1)));
const topLevelName = pipe(topLevel, propOr('NoName', 'name'));
const extract2ndLevel = pipe(pluck('type'), flatten, filter(levelEq(2)));
const convert = pipe(
groupBy(topLevelName),
map(extract2ndLevel),
map(uniq),
toPairs,
map(zipObj(['name', 'typechild']))
);
像这样吗
var output = [{ "name": "Animal", "typechild": [{ "name": "Chicken", "level": 3 }, { "name": "Dog", "level": 2 }] }, { "name": "Food", "typechild": [{ "name": "Chicken", "level": 3 }] }, { "name": "No name", "typechild": [{ "name": "Foo", "level": 2 }, { "name": "Baz", "level": 2 }] }] let out = {}, typechild = {}, k; const data = [{ "title": "Test 1", "type": [{ "name": "Animal", "level": 1 }, { "name": "Food", "level": 1 }, { "name": "Chicken", "level": 3 }] }, { "title": "Test 2", "type": [{ "name": "Foo", "level": 2 }] }, { "title": "Test 3", "type": [{ "name": "Baz", "level": 2 }] }, { "title": "Test 4", "type": [{ "name": "Animal", "level": 1 }, { "name": "Dog", "level": 2 }] }] data.forEach((node) => { k = false; typechild[node.title] = []; node.type && node.type.forEach((t, i) => { if (t.level == 1) { k = true; !out[t.name] ? out[t.name] = { name: t.name, typechild: typechild[node.title] } : out[t.name].typechild = out[t.name].typechild.concat(typechild[node.title]); } else { typechild[node.title].push(t); } if (i == node.type.length - 1 && !k && typechild[node.title].length) { out['No name'] = out['No name'] || { name: 'No name', typechild: [] }; out['No name'].typechild = out['No name'].typechild.concat(typechild[node.title]); } }); }); console.log(JSON.stringify(Object.values(out)));
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