The JavaScript Database, for Node.js, nw.js, electron and the browser
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nedb/browser-version/browser-specific/lib/storage.js

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/**
* Way data is stored for this database
* For a Node.js/Node Webkit database it's the file system
* For a browser-side database it's localStorage when supported
*
* This version is the Node.js/Node Webkit version
*/
function exists (filename, callback) {
// In this specific case this always answers that the file doesn't exist
if (typeof localStorage === 'undefined') { console.log("WARNING - This browser doesn't support localStorage, no data will be saved in NeDB!"); return callback(); }
if (localStorage.getItem(filename) !== null) {
return callback(true);
} else {
return callback(false);
}
}
function rename (filename, newFilename, callback) {
if (typeof localStorage === 'undefined') { console.log("WARNING - This browser doesn't support localStorage, no data will be saved in NeDB!"); return callback(); }
if (localStorage.getItem(filename) === null) {
localStorage.removeItem(newFilename);
} else {
localStorage.setItem(newFilename, localStorage.getItem(filename));
localStorage.removeItem(filename);
}
return callback();
}
function writeFile (filename, contents, options, callback) {
if (typeof localStorage === 'undefined') { console.log("WARNING - This browser doesn't support localStorage, no data will be saved in NeDB!"); return callback(); }
// Options do not matter in browser setup
if (typeof options === 'function') { callback = options; }
localStorage.setItem(filename, contents);
return callback();
}
function appendFile (filename, toAppend, options, callback) {
if (typeof localStorage === 'undefined') { console.log("WARNING - This browser doesn't support localStorage, no data will be saved in NeDB!"); return callback(); }
// Options do not matter in browser setup
if (typeof options === 'function') { callback = options; }
var contents = localStorage.getItem(filename) || '';
contents += toAppend;
localStorage.setItem(filename, contents);
return callback();
}
function readFile (filename, options, callback) {
if (typeof localStorage === 'undefined') { console.log("WARNING - This browser doesn't support localStorage, no data will be saved in NeDB!"); return callback(); }
// Options do not matter in browser setup
if (typeof options === 'function') { callback = options; }
var contents = localStorage.getItem(filename) || '';
return callback(null, contents);
}
function unlink (filename, callback) {
if (typeof localStorage === 'undefined') { console.log("WARNING - This browser doesn't support localStorage, no data will be saved in NeDB!"); return callback(); }
localStorage.removeItem(filename);
return callback();
}
// Nothing done, no directories will be used on the browser
function mkdirp (dir, callback) {
return callback();
}
// Interface
module.exports.exists = exists;
module.exports.rename = rename;
module.exports.writeFile = writeFile;
module.exports.appendFile = appendFile;
module.exports.readFile = readFile;
module.exports.unlink = unlink;
module.exports.mkdirp = mkdirp;