let state = 1;
function step1(resolve,reject){
console.log('1.开始 - 洗菜做饭');
if(state == 1){
resolve('洗菜做饭 - 完成');
}else{
reject('洗菜做饭 - 错误');
}
}
function step2(resolve,reject){
console.log('2.开始 - 坐下来吃饭');
if(state == 1){
resolve('坐下来吃饭 - 完成');
}else{
reject('坐下来吃饭 - 错误');
}
}
function step3(resolve,reject){
console.log('3.开始 - 收拾桌子洗碗');
if(state == 1){
resolve('收拾桌子洗碗 - 完成');
}else{
reject('收拾桌子洗碗 - 错误');
}
}
new Promise(step1).then(function(val){
console.log('val = ' + val);
return new Promise(step2);
}).then(function(val){
console.log('val = ' + val);
return new Promise(step3);
}).then(function(val){
console.log('val = ' + val);
});
