34 lines
942 B
Markdown
34 lines
942 B
Markdown
---
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title: Stringify circular JSON
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type: snippet
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language: javascript
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tags: [object]
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cover: waving-over-lake
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dateModified: 2020-10-22T20:24:30+03:00
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---
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Serializes a JSON object containing circular references into a JSON format.
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- Create a `WeakSet` to store and check seen values, using `WeakSet.prototype.add()` and `WeakSet.prototype.has()`.
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- Use `JSON.stringify()` with a custom replacer function that omits values already in `seen`, adding new values as necessary.
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- ⚠️ **NOTICE:** This function finds and removes circular references, which causes circular data loss in the serialized JSON.
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```js
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const stringifyCircularJSON = obj => {
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const seen = new WeakSet();
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return JSON.stringify(obj, (k, v) => {
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if (v !== null && typeof v === 'object') {
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if (seen.has(v)) return;
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seen.add(v);
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}
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return v;
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});
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};
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```
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```js
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const obj = { n: 42 };
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obj.obj = obj;
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stringifyCircularJSON(obj); // '{"n": 42}'
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```
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