[英]For..of with Symbol.asyncIterator
Why Symbol.asyncIterator is not working?为什么 Symbol.asyncIterator 不工作?
const obj = {
async *[Symbol.asyncIterator] () {
yield 10;
yield 100;
yield 1000;
},
};
for (const val of obj) {
console.log(obj);
}
error: TypeError: obj is not iterable错误:TypeError:obj 不可迭代
for await (const val of obj) {
console.log(obj);
}
error: SyntaxError: for await (... of...) is only valid in async functions and async generators错误:SyntaxError: for await (... of...) 仅在异步函数和异步生成器中有效
(async() => {
for await (const val of obj) {
console.log(val);
}
})()
error: SyntaxError: for await (... of...) is only valid in async functions and async generators错误:SyntaxError: for await (... of...) 仅在异步函数和异步生成器中有效
Because it's an async iterable, you need to await each value:因为它是异步可迭代的,所以您需要等待每个值:
for await (const val of obj) {
console.log(obj);
}
NOTE: this all needs to be wrapped in an async function because Node.js doesn't support top-level await by default:注意:这一切都需要包装在异步 function 因为 Node.js 默认不支持顶级等待:
(async() => {
for await (const val of obj) {
console.log(val);
}
})()
Use await in an async function在异步 function 中使用 await
const obj = { async * [Symbol.asyncIterator]() { yield 10; yield 100; yield 1000; }, }; (async() => { for await (const val of obj) { console.log(val); } })()
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