Function waitUntil

waitUntil(condition, timeout?, interval?): Promise<any>
直到某个函数返回 toBool(true) 的结果(执行完成)
Parameters
- condition: any
  函数
- timeout: number = 0
  超时
- interval: number = 250
  执行间隔
Returns Promise<any>
Example
```
let a = 5;
setTimeout(() => (a = 10), 5000);
waitUntil(() => a === 10).then(() => { console.log(a) });
```