ASYNC/AWAIT SyntaxError:AWAIT仅在异步函数和顶级模块体中有效

Question

我正在做一些非常简单的测试，关于使用csvtojson节点模块将csv文件读取为json格式，我使用下面的代码作为模板

a,b,c
1,2,3
4,5,6
*/
const csvFilePath='<path to csv file>'
const csv=require('csvtojson')
csv()
.fromFile(csvFilePath)
.then((jsonObj)=>{
    console.log(jsonObj);
    /**
     * [
     *  {a:"1", b:"2", c:"3"},
     *  {a:"4", b:"5". c:"6"}
     * ]
     */ 
})
 
// Async / await usage
const jsonArray=await csv().fromFile(csvFilePath);

我主要关注的是

//异步/等待使用

const jsonArray=wait csv（）。fromFile（csvFilePath）；

代码的部分。这是我的密码

// const JSONtoCSV = require("json2csv")
// const FileSystem = require("fs")

async function test()
{
    const data = await CSVtoJSON().fromFile('./input.csv')
    return data
}

let temp = await test()

console.log(temp)

无论我用哪种方法尝试，我总是会出现以下错误

let temp = await test()
           ^^^^^

SyntaxError: await is only valid in async functions and the top level bodies of modules
    at Object.compileFunction (node:vm:352:18)
    at wrapSafe (node:internal/modules/cjs/loader:1031:15)
    at Module._compile (node:internal/modules/cjs/loader:1065:27)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:79:12)
    at node:internal/main/run_main_module:17:47

或

const data = await CSVtoJSON().fromFile('./input.csv');
             ^^^^^

SyntaxError: await is only valid in async functions and the top level bodies of modules
    at Object.compileFunction (node:vm:352:18)
    at wrapSafe (node:internal/modules/cjs/loader:1031:15)
    at Module._compile (node:internal/modules/cjs/loader:1065:27)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:79:12)
    at node:internal/main/run_main_module:17:47

如果我把代码转换成顶级的

const CSVtoJSON = require("csvtojson")
// const JSONtoCSV = require("json2csv")
// const FileSystem = require("fs")

const data = await CSVtoJSON().fromFile('./input.csv')

console.log(data)

我不明白这为什么不起作用。

编辑：我做了@tasobu指出的更改。现在我得到的只是一个回报

const data = (async () => {
    return await CSVtoJSON().fromFile('./input.csv')
})

console.log(data)

Debugger attached.
Promise { <pending> }
Waiting for the debugger to disconnect...

Answer 1

你可以在这里使用生活（在这里阅读更多）

(async function main () {
    // You can use await inside this function block
})();

Answer 2

将整个代码放入一个异步函数中并调用它，这样除了函数外的一些const语句和函数/类声明之外，就不会有其他东西了：

async function main () {
  // All code here, can use await
}

main().then(() => process.exit(0), e => { console.error(e); process.exit(1) })

Answer 3

一个Promise在将来返回一些东西，所以你需要一个等待它的方法。

// const CSVtoJSON = require("json2csv")
// const FileSystem = require("fs")
let temp = undefined;

async function test()
{
    const data = await CSVtoJSON().fromFile('./input.csv')
    // do your stuff with data
    
    temp = data;

    console.log(temp) // at this point you have something in.
    return true
}

test();
console.log(temp) // at this point nothing was there.