In Javascript certain operators are processed before others:
1 + 2 * 3
// 1 + (2 * 3)
// 7 because * has higher precedence than +
1 === 0 + 1
// 1 === (0 + 1)
// true because + has a higher precedence than ===
The MDN has a full breakdown of all operators and their precedence ... except await.
await getFoo() * 2; // await (getFoo() * 2) or (await getFoo()) * 2?
await getFoo() === 5; // await (getFoo() === 5) or (await getFoo()) === 5?
Can anyone explain which operators are processed before/after await?
Right now I feel like I have to add a bunch of parenthesis that are probably unnecessary because I'm not sure what will get handled before/after await. And while I know I should just be able to look this up, even MDN (the gold standard of documentation IMHO) doesn't have the answer.
An AwaitExpression is an UnaryExpression and has the same precedence as delete, void, typeof, +, -, ~, and !, binding stronger than any binary operator.
This is unlike yield which has a precedence lower than anything else except the comma operator. This design decision was made because both yield a+b and await a + await b are scenarios thought to be more common than (yield a) + (yield b) and await (a + b).
来源：https://stackoverflow.com/questions/48218744/what-is-the-operator-precedence-of-await