coolaj86/json-storage.js
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AJ ONeal 2011-08-27 20:44:20 -06:00
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@ -3,6 +3,20 @@ jsonStorage
A light abstraction for DOMStorage (such as localStorage). A light abstraction for DOMStorage (such as localStorage).
Installation
===
Ender.JS (Browser)
ender build json-storage
Node.JS (Server)
npm install localStorage json-storage
Usage
===
Made fo for Node.JS and Ender.JS (browser-side). Made fo for Node.JS and Ender.JS (browser-side).
var localStorage = require('localStorage') var localStorage = require('localStorage')
@ -30,12 +44,29 @@ API
null vs undefined in JSON null vs undefined in JSON
=== ===
Since it is not valid to set `undefined` in JSON, calling `db.set('x')` is the same as `db.remove('x')`. These notes do not reflect a bugs or defects in this library,
they're simply to inform you of a few 'gotchas' inherent in JSON / DOMStorage conversion.
However, `null`, and `"null"` both parse as `null` the "object", but the string (which would be `"\"null\""`). 99.999% of the time these gotchas shouldn't effect you in any way.
If they do, you're probably doing something wrong in the first place.
Therefore, setting a key to `undefined` will remove it from the db, but setting it to `null` will save it.
Yet both values that exist as `null` and values that don't exist will return `null`. It is not valid to set `undefined` in JSON. So setting a key to `undefined` will remove it from the db.
Also `{ "foo": null, "bar": "null" }` will parse as `foo` being `null` but `bar` being `"null"`, much unlike the value `"null"` being parsed on its own. This means that `db.set('x')` is the same as `db.remove('x')`.
To save `undefined`, use `null` instead.
Note that both values that exist as `null` and values that don't exist at all will return `null`.
db.set('existing-key', null);
null === db.get('existing-key');
null === db.get('non-existant-key');
The special case of `null` as `"null"`, aka `"\"null\""`:
`null`, and `"null"` both parse as `null` the "object", instead of one being the string (which would be `"\"null\""`).
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.