[英]How to remove empty arrays in a nested array/object?
I have an array of objects that have array within themselves.我有一个对象数组,这些对象本身就有数组。 I want to loop through the object and delete any empty arrays that I have.
我想遍历对象并删除我拥有的任何空数组。 The object is shown below:
对象如下图:
let a=[{children:[{children:[1,2]},{children:[5,6]}]},
{children:[{children:[]},{children:[5,6]}]},
{children:[{children:[]},{children:[]}]},
{children:[]}]
I am trying to achieve the desired result by applying the code below but I am getting an error saying cannot read property 'children' of undefined.我试图通过应用下面的代码来达到预期的结果,但我收到一条错误消息,说无法读取未定义的属性“子级”。
function removeEmpty(array){
for(var i=array.length-1;i>=0;i--){
if(array[i].children){
if(array[i].children.length){
for(var j=array[i].children.length-1;j=>0;j--){
if(array[i].children[j].children){
removeEmpty(array[i].children[j])
}else{
array[i].splice[j,1]
}
}
if(!array[i].children.length){
array.splice(i,1)
}
}else{
array.splice(i,1)
}
}
}
}
removeEmpty(a)
Expected outcome:预期结果:
expected outcome =[{children:[{children:[1,2]},{children:[5,6]}]},
{children:[{children:[5,6]}]}]
If there are adjustments I can make to the existing code or use a different approach please let me know.如果我可以对现有代码进行调整或使用不同的方法,请告诉我。 Thank you.
谢谢你。
To achieve your goal you can use the .reduce() method.为了实现您的目标,您可以使用.reduce()方法。
const a = [{ children: [{ children: [1, 2] }, { children: [5, 6] }] }, { children: [{ children: [] }, { children: [5, 6] }] }, { children: [{ children: [] }, { children: [] }] }, { children: [] } ] const b = a.reduce((previousValue, currentValue) => { const data = [] if (currentValue.children.length > 0) { currentValue.children.forEach((e) => { if (e.children.length > 0) data.push(e); }); } if (data.length > 0) previousValue.push({children: data}); return previousValue; }, []); console.log(b);
Here is a prune function that reduces a node
with children
.这是一个 prune 函数,用于减少具有
children
的node
。 Just make sure you wrap incoming data in a node with children
.只需确保将传入数据包装在带有
children
的节点中即可。
For each of the nodes children, you filter the children based on the child count.对于每个节点子节点,您可以根据子节点数过滤子节点。
const data = [ { children: [{ children: [1,2] }, { children: [5,6] }] }, { children: [{ children: [] }, { children: [5,6] }] }, { children: [{ children: [] }, { children: [] }] }, { children: [] }, ]; const prune = (node, key = 'children') => node[key].reduce((prev, curr) => (children => children.length ? { [key]: [...prev[key], { [key]: children }] } : prev) (curr[key].filter(child => child[key].length)), { [key]: [] }); const tree = prune({ children: data }); tree.children.forEach(child => console.log(JSON.stringify(child)));
.as-console-wrapper { top: 0; max-height: 100% !important; } .as-console-row-code { font-size: smaller !important; }
var updatedArray = children.filter(item => item.children.length > 0) var updatedArray = children.filter(item => item.children.length > 0)
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