const fs = require('fs');
const obsify = require('obsify');
obsify(fs.readFile)('package.json', 'utf8')
	.map(data => JSON.parse(data))
	.subscribe(data => {
		console.log(data.name);
		//=> 'obsify'
	});
// or observableify all methods in a module
obsify(fs).readFile('package.json', 'utf8')
	.map(data => JSON.parse(data))
	.subscribe(data => {
		console.log(data.name);
		//=> 'obsify'
	});

const obsify = require('obsify');
function fn() {
    return true;
}
fn.method = (data, callback) => {
    setImmediate(() => {
        callback(data, null);
    });
};
// observableify methods but not fn()
const observableFn = obsify(fn, {excludeMain: true});
if (observableFn()) {
    observableFn.method('hi').subscribe(data => {
        console.log(data);
    });
}