[英]Syntax Error: Unexpected Token async()
我一直在关注这个使用GraphQL教程,它告诉我写的代码块在我src/index.js
文件:
const express = require('express');
const bodyParser = require('body-parser');
const {graphqlExpress, graphiqlExpress} = require('apollo-server-express');
const schema = require('./schema');
// 1
const connectMongo = require('./mongo-connector');
// 2
const start = async () => {
// 3
const mongo = await connectMongo();
var app = express();
app.use('/graphql', bodyParser.json(), graphqlExpress({
context: {mongo}, // 4
schema
}));
app.use('/graphiql', graphiqlExpress({
endpointURL: '/graphql',
}));
const PORT = 3000;
app.listen(PORT, () => {
console.log(`Hackernews GraphQL server running on port ${PORT}.`)
});
};
// 5
start();
虽然当我尝试使用以下代码运行代码时: node ./src/index.js
了我这个错误:
const start = async () => {
^
SyntaxError: Unexpected token (
at createScript (vm.js:56:10)
at Object.runInThisContext (vm.js:97:10)
at Module._compile (module.js:542:28)
at Object.Module._extensions..js (module.js:579:10)
at Module.load (module.js:487:32)
at tryModuleLoad (module.js:446:12)
at Function.Module._load (module.js:438:3)
at Module.runMain (module.js:604:10)
at run (bootstrap_node.js:389:7)
at startup (bootstrap_node.js:149:9)
我已经在网上搜索过,看来这可能是由这里的node.js版本引起的,但是我检查了noed.js版本,它是8.3.0
因此如果我不使用Babel,应该支持它。没看错。
这是我的package.json
文件:
{
"name": "graphql-js-tutorial",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"keywords": [],
"author": "",
"license": "ISC",
"dependencies": {
"apollo-server-express": "^1.1.2",
"body-parser": "^1.17.2",
"express": "^4.15.4",
"graphql": "^0.11.2",
"graphql-tools": "^1.2.2",
"mongodb": "^2.2.31"
}
}
异步功能仅在节点8.3起可用
您的代码等同于(没有异步/等待)
const start = () => {
return connectMongo().then(mongo => {
var app = express();
app.use('/graphql', bodyParser.json(), graphqlExpress({
context: {mongo}, // 4
schema
}));
app.use('/graphiql', graphiqlExpress({
endpointURL: '/graphql',
}));
const PORT = 3000;
app.listen(PORT, () => {
console.log(`Hackernews GraphQL server running on port ${PORT}.`)
});
return;
});
};
通过命令node yourAppFile -harmony
启动您的应用程序! 在Node7下的harmony
模式下,可以使用async
功能。
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