1.await必須在async定義的方法中使用

let e = await 78910;
console.log(e);

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2.當await右邊為一個PromiseState為fulfilled的Promise對象時，則返回其PromiseResult值

async function main() {
  let p = new Promise((resolve, reject) => {
    resolve(156);
  });
  let result = await p;
  console.log(result);
  
  let p1 = new Promise((resolve, reject) => {
    reject(177);
  });
  try {
    let result1 = await p1;
  } catch (e) {
    console.log(e);
  }
}
main();

3.當await右邊為為一個PromiseResult為rejected的Promise對象時，需要trycatch獲取其PromiseResult

async function main() {
  let p = new Promise((resolve, reject) => {
    resolve(156);
  });
  let result = await p;
  console.log(result);
  
  let p1 = new Promise((resolve, reject) => {
    reject(177);
  });
  try {
    let result1 = await p1;
  } catch (e) {
    console.log(e);
  }
}
main();

4.如果await右邊為一個非Promise對象，則直接返回右邊內容

async function main() {
  let e = await 78910;
  console.log(e);
}
main();