tj大神的 co库.优雅的解决 nodejs callback无限嵌套问题

github co 项目传送门

个人比较喜欢的,用co库的姿势

测试用函数

function fun1(arg1,arg2,cb){
//dosomthing
cb(null,arg1+'retval'+arg2);
}

function fun2(arg1,cb){
//dosomthing
cb(null,arg1+'retval2');
}

function fun3(arg1,arg2,cb){
//dosomthing
cb(null,arg1+'retval3'+arg2);
}

正常的nodejs

function testFunNormal(targ1,cb){
fun1(targ1+1,targ1+5,function(err,ret){
if(err){
cb(err);
return;
}
fun2(ret+10,function(err,ret){
if(err){
cb(err);
return;
}
fun3(ret+10,ret+5,function(err,ret){
if(err){
cb(err);
return;
}
cb(null,ret+20);
})
})
})
}

//test normal
testFunNormal(666,function(err,ret){
console.log('err:',err,'ret:',ret);
});
//err: null ret: 667retval67110retval210retval3667retval67110retval2520

使用 tj大神的co库后

var co = require('co');

function testCo(targ1,cb){
co(function*(){
let ret = yield (done)=>{fun1(targ1+1,targ1+5,done)};
ret = yield (done)=>{fun2(ret+10,done)};
ret = yield (done)=>{fun3(ret+10,ret+5,done)};
cb(null,ret+20);
}).catch(cb)
}

testCo(666,function(err,ret){
console.log('err:',err,'ret:',ret);
});
//err: null ret: 667retval67110retval210retval3667retval67110retval2520

是不是感觉天空突然开阔了 ^ ^

'use strict';

const co = require('co');

function sleep(ms) {
return function(done){
setTimeout(function(){
done(0,1111,22222)
}, ms);
}
}

function *work() {
var [rr1,rr2] = yield sleep(60);
console.log('rrr',rr1,rr2);
return 'yay';
}

function testCo1(){
co(function *(){
var a = yield work;
var b = yield work;
var c = yield work;

console.log('yay', a);
console.log('yay', b);
console.log('yay' , c);

var res = yield [work, work, work];
console.log(['yay', 'yay', 'yay'], res);
return 'wwwhat'
}).then(function(val){
console.log('aaaa val:',val);
},function(err){
console.log('aaa err:',err);
});

}

function testco2(){
co(function *(){
let ggg = yield function(done){
setTimeout(function(){
done(0,'hahfda');
},1000);
};
console.log('ggg',ggg);
let aaa = yield (done)=>{
setTimeout(()=>{
console.log('aafun ggg:',ggg);
done(null,'ggret');
},1000)
};
console.log('aaaa:',aaa);
return 'ret val';
}).then(function(val){
console.log('aaaa val:',val);
},function(err){
console.log('bbbb err:',err);
}).catch(function(err){
console.log('err err:',err);
});
}

function testco3(){

var aa = co(function*(){
console.time('cot');
console.time('111cot');
let ggg = yield function(done){
done(0,'hahfda');
};
console.timeEnd('111cot');
console.log('ggg',ggg);
let aaa = yield (done)=>{
done(null,'ggret');
};
console.log('aaaa:',aaa);
console.timeEnd('cot');
});

console.time('nocot');

function getggg(done){
done(0,'hahfda');
}

getggg(function(err,ggg){
console.log('ggg',ggg);
function getaaa(done){
done(null,'ggret');
}
getaaa(function(err,aaa){
console.log('aaaa:',aaa);
})

return 'ret val';
});
console.timeEnd('nocot');

}

function isObj1(val){
return Object == val.constructor;
}
function isObj2(val){
return 'object' == typeof val;
}
var obj = {};
console.time('isObj1');
for (let i =0;i<500000;i++){
isObj1(obj);
}
console.timeEnd('isObj1');

console.time('isObj2');
for (let i =0;i<500000;i++){
isObj2(obj);
}
console.timeEnd('isObj2');