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iwillwen/co.js

Last active November 24, 2016 10:15
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Revisions

  1. iwillwen revised this gist Jan 18, 2014. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion co.js
    View file
    Original file line number Diff line number Diff line change
    @@ -6,7 +6,7 @@
    function co(fn) {
    return function(done) {
    done = done || function() {};

    var gen = fn();

    function next(value) {
  2. iwillwen revised this gist Jan 18, 2014. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion co.js
    View file
    Original file line number Diff line number Diff line change
    @@ -80,7 +80,7 @@ co(function *() {
    var arr = yield foo();
    var obj = yield bar();
    var nor = yield echo('foobar');
    var arr2 = yield [echo('foo'), echo('bar')];
    var arr2 = [yield echo('foo'), yield echo('bar')];

    console.log(arr, obj, nor, arr2);
    })();
  3. iwillwen created this gist Jan 18, 2014.
    86 changes: 86 additions & 0 deletions co.js
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,86 @@
    /**
    * A simple co
    * @param {Function} fn Generator Function
    * @return {Function} callback
    */
    function co(fn) {
    return function(done) {
    done = done || function() {};

    var gen = fn();

    function next(value) {
    var ret = gen.next(value);
    if (ret.done) return done(null, ret.value);

    switch(true) {
    // Function
    case 'function' === typeof ret.value:
    // Standard Callback
    ret.value(function(err, value) {
    if (err) return done(err);
    next(value);
    });
    break;
    // Promise
    case !!ret.value.then:
    // see http://promises-aplus.github.io/promises-spec/#the__method
    ret.value.then(next, done);
    break;
    // Array
    case Array.isArray(ret.value):
    var n = ret.value.length;
    var res = new Array(n);
    ret.value.forEach(function(row, index) {
    row(function(err, value) {
    if (err) return done(err);
    // Keep it's order
    res[index] = value;
    --n || next(res);
    });
    });
    break;
    // Object
    case ret.value === Object(ret.value):
    var res = {};
    (function loop(keys, key, err, value) {
    if (err) return done(err);
    if (key && value) res[key] = value;
    var curr = keys.shift();
    if (curr) ret.value[curr](loop.bind(null, keys, curr))
    else next(res);
    })(Object.keys(ret.value));
    break;
    }
    }

    next();
    };
    }

    function echo(content) {
    return function(callback) {
    callback(null, content);
    };
    };
    function foo() {
    var a = echo('foo');
    var b = echo('bar');
    return [a, b];
    }
    function bar() {
    var a = echo('foo');
    var b = echo('bar');
    return {
    a: a,
    b: b
    };
    }
    co(function *() {
    var arr = yield foo();
    var obj = yield bar();
    var nor = yield echo('foobar');
    var arr2 = yield [echo('foo'), echo('bar')];

    console.log(arr, obj, nor, arr2);
    })();