Sketch Plugin functions for working with files.

Sketch Plugin Snippet - Managing Files.js

var writeTextToFile = function(text, filePath) {
    var t = [NSString stringWithFormat:@"%@", text],
    f = [NSString stringWithFormat:@"%@", filePath];
    return [t writeToFile:f atomically:true encoding:NSUTF8StringEncoding error:nil];
}

var readTextFromFile = function(filePath) {
    var fileManager = [NSFileManager defaultManager];
    if([fileManager fileExistsAtPath:filePath]) {
        return [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
    }
    return nil;
}

var jsonFromFile = function(filePath, mutable) {
    var data = [NSData dataWithContentsOfFile:filePath];
	var options = mutable == true ? NSJSONReadingMutableContainers : 0
	return [NSJSONSerialization JSONObjectWithData:data options:options error:nil];
}

var saveJsonToFile = function(jsonObj, filePath) {
    writeTextToFile(stringify(jsonObj), filePath);
}

var stringify = function(obj, prettyPrinted) {
    var prettySetting = prettyPrinted ? NSJSONWritingPrettyPrinted : 0,
    jsonData = [NSJSONSerialization dataWithJSONObject:obj options:prettySetting error:nil];
    return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}

var createTempFolderNamed = function(name) {
    var tempPath = getTempFolderPath(name);
    createFolderAtPath(tempPath);
    return tempPath;
}

var getTempFolderPath = function(withName) {
    var fileManager = [NSFileManager defaultManager],
    cachesURL = [[fileManager URLsForDirectory:NSCachesDirectory inDomains:NSUserDomainMask] lastObject],
    withName = (typeof withName !== 'undefined') ? withName : (Date.now() / 1000),
    folderName = [NSString stringWithFormat:"%@", withName];
    return [[cachesURL URLByAppendingPathComponent:folderName] path];
}

var createFolderAtPath = function(pathString) {
    var fileManager = [NSFileManager defaultManager];
    if([fileManager fileExistsAtPath:pathString]) return true;
    return [fileManager createDirectoryAtPath:pathString withIntermediateDirectories:true attributes:nil error:nil];
}

var removeFileOrFolder = function(filePath) {
    [[NSFileManager defaultManager] removeItemAtPath:filePath error:nil];
}

Thanks for sharing!

please add it to https://github.com/turbobabr/Sketch-Plugins-Cookbook