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Web Storage API
Deno 1.10 introduced the
Web Storage API
which provides an API for storing string keys and values. Persisting data works
similar to a browser, and has a 10MB storage limit. The global
object only persists data for the current execution context, while
localStorage persists data from execution to execution.
In a browser,
localStorage persists data uniquely per origin (effectively the
protocol plus hostname plus port). As of Deno 1.16, Deno has a set of rules to
determine what is a unique storage location:
- When using the
--locationflag, the origin for the location is used to uniquely store the data. That means a location of
http://example.com:80/would all share the same storage, but
https://example.com/would be different.
- If there is no location specifier, but there is a
--configconfiguration file specified, the absolute path to that configuration file is used. That means
deno run --config deno.jsonc a.tsand
deno run --config deno.jsonc b.tswould share the same storage, but
deno run --config tsconfig.json a.tswould be different.
- If there is no configuration or location specifier, Deno uses the absolute
path to the main module to determine what storage is shared. The Deno REPL
generates a "synthetic" main module that is based off the current working
denois started from. This means that multiple invocations of the REPL from the same path will share the persisted
This means, unlike versions prior to 1.16,
localStorage is always available in
the main process.
The following snippet accesses the local storage bucket for the current origin
and adds a data item to it using
localStorage.setItem("myDemo", "Deno App");
The syntax for reading the localStorage item is as follows:
const cat = localStorage.getItem("myDemo");
The syntax for removing the localStorage item is as follows:
The syntax for removing all the localStorage items is as follows: