Uniapp storing data to local files and reading local file data code examples

        // Method for reading local files Parameter 1 is the file name, and parameter 2 is the callback method used to process the obtained file data		fetchFileData(fileName,callback) {
			(
				.PUBLIC_DOWNLOADS, // Root directory in the file system				fs => {
					// Create or open a file, which is the root directory operation object, directly fs represents the current operation object					(fileName, {
						create: true // Create if the file does not exist					}, fileEntry => {
						// The path of the file in the phone						('Path of file in phone', )
						(function(file) {
							var fileReader = new ();
							("getFile:" + (file));
							(file, "utf-8")
							 = function(res) { //Callback event after successful reading of file content								//Readed file content information								('The last reading of the file is=======', )
								callback()
							}
						});
					}, e => {
						('Error 111', "getFile failed: " + );
					});
				},
				e => {
					('Error 222', );
				}
			);
		},

// Parameter 1 is the file name Parameter 2 is the file content Parameter 3 is the callback parametersaveFile(fileName,fileInfo,callback) {
			// Request local file system object			(
				.PUBLIC_DOWNLOADS, // Root directory in the file system				fs => {
					// Create or open a file, which is the root directory operation object, directly fs represents the current operation object					(fileName, {
						create: true // Create if the file does not exist					}, fileEntry => {
						// The path of the file in the phone						('The path to the last file in the phone========', )
						(writer => {
							// Callback function that successfully completes writing to the file							 = e => {
								("Writing data successfully");
								callback(true)
							};
							// Write data							((fileInfo));
						})
					}, e => {
						callback(false)
						('Error 111', "getFile failed: " + );
					});
				},
				e => {
					('Error 222', );
					callback(false)
				}
			);
		},