my-load-data

This is my module that loads files of a few format including JSON, YAML and plain JS for me.

installation

 $ npm install my-load-data

Examples

Basic usage

const mld = require('my-load-data');
 
// mld.fromFile() returns Promise
mld.fromFile('./data/foo.json').then(obj=>console.log(obj))
.catch(err=>console.error(err));
 
// It can also load all files in a directory
mld.fromDirectory('./data').then(obj=>console.log(obj))
.catch(err=>console.error(err));
/*
If ./data contains foo.json, bar.yaml and baz.js:
 
{
    "foo": {...},
    "bar": {...},
    "baz": {...},
}
*/
 
// Array of paths is accepted
mld.fromDirectory(['./data', './data1']).then(obj=>console.log(obj));

Loader

You can instantiate Loaders instead of using the default Loader. Loaders can be customized through addHandler (see API below).

const mld = require('my-load-data');
 
const loader = new mld.Loader();
 
loader.fromFile('./data/foo.json').then(obj=>console.log(obj));

API

mld.fromFile(path[, options]) / loader.fromFile(path[, options])

• Return value: Promise<any>
• path: string; Path to the file to load data from.
• options:
  • mtime: boolean | string; If the value is truthy, mtime of the file is added to the result object. If the value is string, it is used as the field name. The default field name is $mtime.
  • cache: Object; If this option is used, unchanged files (determined by mtime) is not loaded and its value is taken from cache. The cache should be the return value of previous call to fromFile with mtime enabled (When cache is used, mtime is automatically enabled).
  • nocacheFilter: RegExp | Function; Filter function to temporally disable cache based on file names. If the function returns true, the file is newly loaded regardless of its time.

mld.fromDirectory(path[, options]) / loader.fromDirectory(path[, options])

• Return value: Promise<any>
• path: string | Array; Path to the directory to load data from.
• options: See above.

If path is an Array, directories are visited sequentially.

loader.addHandler(ext, handler)

• ext: string; Name of extension to add handler.
• handler: (path: string)=>any;

Use this method to add a custom handler. handler is passed an absolute path of a file to load: path.

As shown in the example below, return value of handler is treated as a result of loading. handle also can return Promise for asynchronous operations.

example

const fs = require('fs');
const mld = require('my-load-data');
 
// add a handler to load .txt file as string.
mld.addHandler('txt', path=> fs.readFileSync(path, 'utf8'));
 
// Now mld can load .txt file
mld.fromFile('data/hoge.txt').then(str=>console.log(str));
 
// fromDirectory now finds and handles .txt files
mld.fromDirectory('data').then(obj=>console.log(obj.hoge));

Gimmicks

• json file is loaded using JSON.parse.
• yaml file is loaded using js-yaml. This module uses safeLoad. To customize this behavior, add a custom handler using addHandler.
• js file is loaded using require. js files can export Promises to make an asynchronous operation.

Changelog

• v1.1.0 (2016-xx-xx) Add the mtime, cache and nocacheFilter option for me.
• v1.0.0 (2016-06-10)

License

MIT

Contribution

Following npm scripts are useful:

• npm build: build source files into dist/.
• npm watch: watch changes in lib/ and test/; on changes, compiling, linting and testing are triggered.
• npm clean: removes dist/ directory.