如何为 JavaScript 中嵌套 JSON 结构中的每个对象添加属性？

Question

Let's suppose I have an API response that looks like this:

const data = {
  users: [
    { name: "John", teams: [{ name: "Liverpool" }] },
    { name: "Sam", teams: [{ name: "MC" }, { name: "United" }] },
  ],
  photos: [
    { id: "123", types: ["JPG", "PNG"], comments: [{ description: "sample photo" }] },
  ],
};

I want to transform it by adding the rid property to each object .

const data = {
  rid: "ABC",
  users: [
    { rid: "ABC", name: "John", teams: [{ rid: "ABC", name: "Liverpool" }] },
    { rid: "ABC", name: "Sam", teams: [{ rid: "ABC", name: "MC" }, { rid: "ABC", name: "United" }] },
  ],
  photos: [
    { rid: "ABC", id: "123", types: ["JPG", "PNG"], comments: [{ rid: "ABC", description: "sample photo" }] },
  ],
};

How can I do so? I think there is some kind of recursion involved but I haven't been able to draft a solution?

Thanks.

Answer 1

First off, in StackOverflow, you should always show your own work. Even if you weren't able to get a complete solution, please show us what you've tried and tell us where it seemed to go wrong. I would not be answering this question except that there are already two other reasonable answers here.

---

I have a strong aversion to modifying input data, so I wrote a version that creates a copy with that property included on all Object nodes. It looks like this:

 const addProp = (name, val) => (o) => Array .isArray (o) ? o .map (addProp (name, val)) : Object (o) === o ? Object .fromEntries ([ [name, val], ...Object .entries (o) .map (([k, v]) => [k, addProp (name, val) (v)]) ]) : o const data = {users: [{name: "John", teams: [{name: "Liverpool"}]}, {name: "Sam", teams: [{name: "MC"}, {name: "United"}]},], photos: [{id: "123", types: ["JPG", "PNG"], comments: [{description: "sample photo"}]}]} console .log (addProp ('rid', 'ABC') (data))

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We process in three ways, based on whether our input is an Array , an Object , or something else. If it's neither, we return the value intact. If it's an array, we map a recursive call to the same function over its values. For an object, we split it into name-value pairs, mapping the values with a recursive call and adding one for our new property, then we fold these name-value entries back into an object.

Answer 2

Firstly the OP is not going to alter a JSON object. JSON is a string based standardized data interchange format and a JavaScript namespace with static methods.

But the OP is going to recursively traverse/walk a JSON-conform object-type.

Thus the implementation of such a function needs to take into account just object-types and arrays.

In case of an array-type the recursive call takes place forEach array-item . In case of an object-type all values of the object's own enumerable keys/properties will be processed recursively.

For any object-type in addition the assign ment of a provided custom object (one or more entries) takes place.

The beneath provided function provides as feature the possibility to define the minimum object-level from where an assignement is going to be applied.

 function recursivelyAssignDataToEveryObjectType(type, data, startLevel = 0, level = 0) { if (Array.isArray(type)) { type .forEach(item => recursivelyAssignDataToEveryObjectType(item, data, startLevel, level + 1) ); } else if (type && 'object' === typeof type) { Object .values(type) .forEach(value => recursivelyAssignDataToEveryObjectType(value, data, startLevel, level + 1) ); if (level >= startLevel) { Object.assign(type, data); } } } const data = { users: [ { name: "John", teams: [{ name: "Liverpool" }] }, { name: "Sam", teams: [{ name: "MC" }, { name: "United" }] }, ], photos: [ { id: "123", types: ["JPG", "PNG"], comments: [{ description: "sample photo" }] }, ], }; recursivelyAssignDataToEveryObjectType(data, { rid: "ABC" }, 2); console.log({ data });

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Answer 3

You just need to iterate through object with recursive function.

Try below snippet.

 const data = { users: [ { name: 'John', teams: [{ name: 'Liverpool' }] }, { name: 'Sam', teams: [{ name: 'MC' }, { name: 'United' }] }, ], photos: [ { id: '123', types: ['JPG', 'PNG'], comments: [{ description: 'sample photo' }] }, { key: null }, // Fixed null values ], } function addProperty(obj, key, val) { if (!obj || typeof obj !== 'object') return if (!Array.isArray(obj)) obj[key] = val Object.values(obj).forEach((obj) => addProperty(obj, key, val)) } addProperty(data, 'rid', 'ABC') console.log(data)