react native tips
Demo
console.log('aaaaa0');
setTimeout(() => {
console.log('aaaaa1');
}, 0);
console.log('aaaaa3');
new Promise((resolve, reject) => {
console.log('aaaaa4')
resolve('aaaaa4');
console.log('aaaaa5');
resolve('aaaaa5');
console.log('aaaaa6');
reject('aaaaa6')
console.log('aaaaa7');
reject('aaaaa7')
console.log('aaaaa7.0');
}).then((result) => {
console.log('aaaaa8');
console.log(result);
console.log('aaaaa9');
}).catch(e => {
console.log('aaaaa10');
console.log(e);
console.log('aaaaa11');
});
console.log('aaaaa12');
this.setState({
countryId: 2
}, () => {
console.log('aaaaa2', this.state.countryId);
});
this.setState({
countryId: 3
}, () => {
console.log('aaaaa13', this.state.countryId);
});
console.log('aaaaa14');
上面输出结果为
aaaaa0
aaaaa3
aaaaa4
aaaaa5
aaaaa6
aaaaa7
aaaaa7.0
aaaaa12
aaaaa14
aaaaa2 3
aaaaa13 3
aaaaa8
aaaaa4
aaaaa9
aaaaa1
有兴趣的可以把上面的顺序打乱，再观察下执行顺序
出现上述的结果，可以暂时归纳为下面几个结果：
