Class: Persist

Persist

new Persist()

The persistent storage class handles loading and saving data to browser storage.
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Methods

(static) addStep(encode, decode, indexopt)

Adds an encode/decode step to the persistent storage system so that you can add custom functionality.
Parameters:
Name Type Attributes Description
encode function The encode method called with the data from the previous encode step. When your method is complete it MUST call the callback method. If you provide anything other than false to the err parameter the encoder will fail and throw an error.
decode function The decode method called with the data from the previous decode step. When your method is complete it MUST call the callback method. If you provide anything other than false to the err parameter the decoder will fail and throw an error.
index Number <optional>
 Optional index to add the encoder step to. This allows you to place a step before or after other existing steps. If not provided your step is placed last in the list of steps. For instance if you are providing an encryption step it makes sense to place this last since all previous steps will then have their data encrypted by your final step.
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(static) addStep(encode, decode)

Adds an encode/decode step to the persistent storage system so that you can add custom functionality.
Parameters:
Name Type Description
encode function The encode method called with the data from the previous encode step. When your method is complete it MUST call the callback method. If you provide anything other than false to the err parameter the encoder will fail and throw an error.
decode function The decode method called with the data from the previous decode step. When your method is complete it MUST call the callback method. If you provide anything other than false to the err parameter the decoder will fail and throw an error.
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(static) addStep(obj)

Adds an encode/decode step to the persistent storage system so that you can add custom functionality.
Parameters:
Name Type Description
obj function The object to encode / decode.
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decode(val, finished)

Starts a decode waterfall process.
Parameters:
Name Type Description
val * The data to be decoded.
finished function The callback to pass final data to.
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driver(val) → {*}

Gets / sets the driver used when persisting data.
Parameters:
Name Type Description
val String Specify the driver type (LOCALSTORAGE, WEBSQL or INDEXEDDB)
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Returns:
Type
*

drop(key, callbackopt)

Deletes data in persistent storage stored under the passed key.
Parameters:
Name Type Attributes Description
key String The key to drop data for in the storage.
callback function <optional>
 The method to call when the data is dropped.
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encode(val, finished)

Starts an encode waterfall process.
Parameters:
Name Type Description
val * The data to be encoded.
finished function The callback to pass final data to.
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init(db)

The init method that can be overridden or extended.
Parameters:
Name Type Description
db Db The ForerunnerDB database instance.
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load(key, callbackopt)

Loads and decodes data from the passed key.
Parameters:
Name Type Attributes Description
key String The key to retrieve data from in the persistent storage.
callback function <optional>
 The method to call when the load process has completed.
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mode(type) → {*}

Gets / sets the persistent storage mode (the library used to persist data to the browser - defaults to localForage).
Parameters:
Name Type Description
type String The library to use for storage. Defaults to localForage.
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Returns:
Type
*

persistedSize(target, callback)

determine byte size of a persisted object, either entire DB or specific collection
Parameters:
Name Type Description
target string | object either a string (collection name) or an object (DB)
callback persistedSizeCallback method to call when size determination is done - mandatory for obtaining a result!
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save(key, data, callbackopt)

Encodes passed data and then stores it in the browser's persistent storage layer.
Parameters:
Name Type Attributes Description
key String The key to store the data under in the persistent storage.
data Object The data to store under the key.
callback function <optional>
 The method to call when the save process has completed.
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Members

localforage

The local forage library.
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