javascript将嵌套字典转换为树状数组结构

Question

I have a sample input of strings in the form of - "abc", "ade", etc.

I want to convert the string parts separated by "." to be represented in a tree structure.

So, I wrote the below function to create a nested dictionary object from such an array of input -

function items_to_tree(items) {
    var arr = {};
    items.forEach(function(item){
        var parts = item.split(".");
        var last = parts.pop();
        var cursor = arr;
        parts.forEach(function(part){
            if(!cursor[part]) cursor[part] = {};
            cursor = cursor[part];
        });
        cursor[last] = {};
    });
    return arr;
}

So, for example If I give the below sample input to this function -

var items = ["a.b", "a.c", "b.c", "a.c", "a.c.d", "a.b.d"]

I get {"a":{"b":{"d":{}},"c":{"d":{}}},"b":{"c":{}}} as expected.

But, I want the output to be in a format similar to this -

[{name: "a", children: [{name: "b", children: [{name: "d", children: []}]}]}, {name: "c", children: [{name: "d", children: []}]}, {name: "b", children: [{name: "c", children: []}]}]

Is there any way the items_to_tree function can be modified to return such output, or can the intermediate output from the items_to_tree [the nested dictionary] be transformed into this tree like javascript object array.

Answer 1

You could seach in the nested array for a given name and use that object or create a new one.

 var items = ["ab", "ac", "bc", "ac", "acd", "abd"], result = []; items.forEach(function (path) { path.split('.').reduce(function (level, key) { var temp = level.find(({ name }) => key === name); if (!temp) { temp = { name: key, children: [] }; level.push(temp); } return temp.children; }, result); }); console.log(result); 

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Answer 2

I would write a second function for the final data conversion. Your items_to_tree is pretty generic and reusable. Converting this tree to the desired format can be done in a few lines:

function tree_to_format(tree) {
  return Object
    .keys(tree)
    .map(k => ({ name: k, children: tree_to_format(tree[k]) }))
};

Now, you can compose the function you need by piping the result of items_to_tree to tree_to_format :

 function items_to_tree(items) { var arr = {}; items.forEach(function(item){ var parts = item.split("."); var last = parts.pop(); var cursor = arr; parts.forEach(function(part){ if(!cursor[part]) cursor[part] = {}; cursor = cursor[part]; }); cursor[last] = {}; }); return arr; } function tree_to_format(tree) { return Object .keys(tree) .map(k => ({ name: k, children: tree_to_format(tree[k]) })) }; console.log( tree_to_format( items_to_tree(["ab", "ac", "bc", "ac", "acd", "abd"]) ) ); // or even: const compose = (f, g) => x => f(g(x)); const items_to_format = compose(tree_to_format, items_to_tree);