Re-implement tj/co in 15 lines

co-in-15-lines.js

function run(fn) {
    var pointer = fn();
    var next = function(result) {
        if (result.value.then && typeof result.value.then === 'function') {
            result.value.then(function(data) {
                var out = pointer.next(data);
                if (!out.done) next(out);
            });
        } else {
            var out = pointer.next(result.value);
            if (!out.done) next(out);
        }
    }
    next(pointer.next());
}

run-Example-1.js

'use strict';
var request = require('superagent');

// Use case #1: Working with promises
run(function*() {
    var result = (yield request.get('http://huytd.github.io/posts/hello.md')).text;
    console.log('Case #1:', result);
});

// Output: 
// Case #1: Hi! I'm Huy! Nice to meet you!

run-Example-2.js

'use strict';
var request = require('superagent');

// Use case #2: Get the value directly
run(function*() {
    var result = yield 100;
    console.log('Case #2:', result, '\n');
});

// Output:
// Case #2: 100

run-Example-3.js

'use strict';
var request = require('superagent');

// Use case #3: Multiple async calls
run(function*(){
    var r1 = (yield request.get('http://huytd.github.io/posts/hello.md'));
    var r2 = yield '8th May\n';
    var r3 = (yield request.get('http://huytd.github.io/posts/hello.md'));

    console.log('Case #3:\n');
    console.log('> r1:', r1.text);
    console.log('> r2:', r2);
    console.log('> r3:', r3.text);
});

// Output:
// Case #3:
// > r1: Hi! I'm Huy! Nice to meet you!
// > r2: 8th May
// > r3: Hi! I'm Huy! Nice to meet you!