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- # structuredClone polyfill
-
- [](https://www.npmjs.com/package/@ungap/structured-clone) [](https://github.com/ungap/structured-clone/actions) [](https://coveralls.io/github/ungap/structured-clone?branch=main)
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- An env agnostic serializer and deserializer with recursion ability and types beyond *JSON* from the *HTML* standard itself.
-
- * [Supported Types](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm#supported_types)
- * *not supported yet*: Blob, File, FileList, ImageBitmap, ImageData, and ArrayBuffer, but typed arrays are supported without major issues, but u/int8, u/int16, and u/int32 are the only safely suppored (right now).
- * *not possible to implement*: the `{transfer: []}` option can be passed but it's completely ignored.
- * [MDN Documentation](https://developer.mozilla.org/en-US/docs/Web/API/structuredClone)
- * [Serializer](https://html.spec.whatwg.org/multipage/structured-data.html#structuredserializeinternal)
- * [Deserializer](https://html.spec.whatwg.org/multipage/structured-data.html#structureddeserialize)
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- Serialized values can be safely stringified as *JSON* too, and deserialization resurrect all values, even recursive, or more complex than what *JSON* allows.
-
-
- ### Examples
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- Check the [100% test coverage](./test/index.js) to know even more.
-
- ```js
- // as default export
- import structuredClone from '@ungap/structured-clone';
- const cloned = structuredClone({any: 'serializable'});
-
- // as independent serializer/deserializer
- import {serialize, deserialize} from '@ungap/structured-clone';
-
- // the result can be stringified as JSON without issues
- // even if there is recursive data, bigint values,
- // typed arrays, and so on
- const serialized = serialize({any: 'serializable'});
-
- // the result will be a replica of the original object
- const deserialized = deserialize(serialized);
- ```
-
- #### Global Polyfill
- Note: Only monkey patch the global if needed. This polyfill works just fine as an explicit import: `import structuredClone from "@ungap/structured-clone"`
- ```js
- // Attach the polyfill as a Global function
- import structuredClone from "@ungap/structured-clone";
- if (!("structuredClone" in globalThis)) {
- globalThis.structuredClone = structuredClone;
- }
-
- // Or don't monkey patch
- import structuredClone from "@ungap/structured-clone"
- // Just use it in the file
- structuredClone()
- ```
-
- **Note**: Do not attach this module's default export directly to the global scope, whithout a conditional guard to detect a native implementation. In environments where there is a native global implementation of `structuredClone()` already, assignment to the global object will result in an infinite loop when `globalThis.structuredClone()` is called. See the example above for a safe way to provide the polyfill globally in your project.
-
- ### Extra Features
-
- There is no middle-ground between the structured clone algorithm and JSON:
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- * JSON is more relaxed about incompatible values: it just ignores these
- * Structured clone is inflexible regarding incompatible values, yet it makes specialized instances impossible to reconstruct, plus it doesn't offer any helper, such as `toJSON()`, to make serialization possible, or better, with specific cases
-
- This module specialized `serialize` export offers, within the optional extra argument, a **lossy** property to avoid throwing when incompatible types are found down the road (function, symbol, ...), so that it is possible to send with less worrying about thrown errors.
-
- ```js
- // as default export
- import structuredClone from '@ungap/structured-clone';
- const cloned = structuredClone(
- {
- method() {
- // ignored, won't be cloned
- },
- special: Symbol('also ignored')
- },
- {
- // avoid throwing
- lossy: true,
- // avoid throwing *and* looks for toJSON
- json: true
- }
- );
- ```
-
- The behavior is the same found in *JSON* when it comes to *Array*, so that unsupported values will result as `null` placeholders instead.
-
- #### toJSON
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- If `lossy` option is not enough, `json` will actually enforce `lossy` and also check for `toJSON` method when objects are parsed.
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- Alternative, the `json` exports combines all features:
-
- ```js
- import {stringify, parse} from '@ungap/structured-clone/json';
-
- parse(stringify({any: 'serializable'}));
- ```
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