const promise = new Promise(function(resolve, reject){
setTimeout(function(){
try {
let c = 6 / 2 ;
resolve(c);
console.log(c)
}catch(ex) {
reject(ex);
}
}, 1000)
})
promise.then(function(value) {
console.log(value)
},function(err){
console.error(err.message)
})
运行结果是3
catch的使用
const promise = new Promise(function(resolve, reject){
setTimeout(function(){
try {
let c = 6 / 2 ;
resolve(c);
console.log(c)
}catch(ex) {
reject(ex);
}
}, 1000)
})
promise.then(function(value) {
console.log(value)
}) .catch(function (err) {
console.error(err.message);
})
拒绝的情形
const promise = new Promise(function(resolve, reject){
setTimeout(function(){
try {
let c = 6 / 0 ;
resolve(c);
console.log(c)
}catch(ex) {
reject(ex);
}
}, 1000)
})
promise.then(function(value) {
console.log(value)
}) .catch(function (err) {
console.error(err.message);
})
输出
Infinity
没有用catch也输出的是一样啊
const promise = new Promise(function(resolve, reject){
setTimeout(function(){
try {
let c = 6 / 0 ;
resolve(c);
console.log(c)
}catch(ex) {
reject(ex);
}
}, 1000)
})
promise.then(function(value) {
console.log(value)
},function(err){
console.error(err.message)
})
