96 lines
2.6 KiB
Markdown
96 lines
2.6 KiB
Markdown
JsonStorage
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====
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A light, sensible abstraction for DOMStorage (such as localStorage).
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Installation
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===
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Bower (Browser)
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```bash
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bower install json-storage
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# or
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wget https://raw2.github.com/coolaj86/json-storage-js/master/json-storage.js
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```
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Node.JS (Server)
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```bash
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npm install localStorage json-storage
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```
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Usage
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===
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Made for Node.js and Bower (browser-side).
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var localStorage = require('localStorage')
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, JsonStorage = require('json-storage').JsonStorage
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, store = JsonStorage.create(localStorage, 'my-widget-namespace', { stringify: false })
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, myValue = {
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foo: "bar"
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, baz: "quux"
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}
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;
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store.set('myKey', myValue);
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myValue = store.get('myKey');
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NOTE: When using with Node and the `localStorage` module,
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you may wish to pass the `{ stringify: false }` option to prevent double stringification.
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API
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===
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* `JsonStorage.create(DOMStorage, namespace)`
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* `DOMStorage` should be globalStorage, sessionStorage, or localStorage
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* `namespace` is optional string which allows multiple non-conflicting storage containers
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* `store.get(key)`
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* `store.set(key, value)`
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* `store.remove(key)`
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* `store.clear()`
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* `store.keys()`
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* `store.size()`
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* `store.toJSON()`
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* `JSON.stringify(store)`
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Upgrading from localStorage and 1.0.x to 1.1.x
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===
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1.1.x automatically attempts to upgrade your DOMStorage to use namespaces in backwards-compatible way.
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However, you can prevent this behaviour:
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localStorage.getItem('_json-storage-namespaced_', true);
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null vs undefined in JSON
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===
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These notes do not reflect a bugs or defects in this library,
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they're simply to inform you of a few 'gotchas' inherent in JSON / DOMStorage conversion.
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99.999% of the time these gotchas shouldn't effect you in any way.
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If they do, you're probably doing something wrong in the first place.
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It is not valid to set `undefined` in JSON. So setting a key to `undefined` will remove it from the store.
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This means that `store.set('x')` is the same as `store.remove('x')`.
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To save `undefined`, use `null` instead.
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Note that both values that exist as `null` and values that don't exist at all will return `null`.
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store.set('existing-key', null);
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null === store.get('existing-key');
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null === store.get('non-existant-key');
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The special case of `null` as `"null"`, aka `"\"null\""`:
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`null`, and `"null"` both parse as `null` the "object", instead of one being the string (which would be `"\"null\""`).
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Objects containing `null`, however, parse as expected `{ "foo": null, "bar": "null" }` will parse as `foo` being `null` but `bar` being `"null"`, much unlike the value `"null"` being parsed on its own.
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