51 lines
1.9 KiB
Markdown
51 lines
1.9 KiB
Markdown
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# Serialization
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Math.js has a number of data types like `Matrix`, `Complex`, and `Unit`. These
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types are instantiated JavaScript objects. To be able to store these data types
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or send them between processes, they must be serialized. The data types of
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math.js can be serialized to JSON. Use cases:
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- Store data in a database or on disk.
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- Interchange of data between a server and a client.
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- Interchange of data between a web worker and the browser.
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Math.js types can be serialized using JavaScript's built-in `JSON.stringify`
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function:
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```js
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const x = math.complex('2 + 3i')
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const str = JSON.stringify(x, math.replacer)
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console.log(str)
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// outputs a string '{"mathjs":"Complex","re":2,"im":3}'
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```
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> IMPORTANT: in most cases works, serialization correctly without
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> passing the `math.replacer` function as second argument. This is because
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> in most cases we can rely on the default behavior of JSON.stringify, which
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> uses the `.toJSON` method on classes like `Unit` and `Complex` to correctly
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> serialize them. However, there are a few special cases like the
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> number `Infinity` which does require the replacer function in order to be
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> serialized without losing information: without it, `Infinity` will be
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> serialized as `"null"` and cannot be deserialized correctly.
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>
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> So, it's best to always pass the `math.replacer` function to prevent
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> weird edge cases.
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In order to deserialize a string, containing math.js data types, `JSON.parse`
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can be used. In order to recognize the data types of math.js, `JSON.parse` must
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be called with the reviver function of math.js:
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```js
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const json = '{"mathjs":"Unit","value":5,"unit":"cm","fixPrefix":false}'
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const x = JSON.parse(json, math.reviver) // Unit 5 cm
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```
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Note that if math.js is used in conjunction with other data types, it is
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possible to use multiple reviver functions at the same time by cascading them:
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```js
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const reviver = function (key, value) {
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return reviver1(key, reviver2(key, value))
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}
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```
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