我正在尝试读取在gatsby-config.js文件中定义的siteMetadata对象的内容，但是每次尝试都会出现此错误
event queue我正在将Gatsby与打字稿一起使用。我在function main {
begin {
$global:latestPortMessage = ''
$form = createForm
$port = createAndOpenPort
}
process {
subscribeToPortEvents $port
[void]$form.ShowDialog()
}
end {
}
}
##### GUI CREATION HELPERS
function createForm {
Add-Type -AssemblyName System.Windows.Forms
[Windows.Forms.Application]::EnableVisualStyles()
$FormStartPosition = [System.Windows.Forms.FormStartPosition]::CenterScreen
$form = New-Object system.Windows.Forms.Form
$form.AutoSize = $true
$form.text = "Serial-test"
$form.TopMost = $false
$form.StartPosition = $FormStartPosition
$clickButton = createClickButton
$closeButton = createCloseButton
$form.controls.add($clickButton)
$form.controls.add($closeButton)
$form
}
function createClickButton {
$button = New-Object system.Windows.Forms.Button
$button.BackColor = "#e66b6b"
$button.text = "Click"
$button.width = 100
$button.height = 100
$button.Font = 'Microsoft Sans Serif,10,style=Bold'
$button.margin = 0
$button.Add_Click({ onClickButton })
$button
}
function createCloseButton {
$button = New-Object system.Windows.Forms.Button
$button.BackColor = "#e66b6b"
$button.text = "Close"
$button.width = 100
$button.height = 100
$button.location = '100,0'
$button.Font = 'Microsoft Sans Serif,10,style=Bold'
$button.margin = 0
$button.Add_Click({ onCloseButton })
$button
}
function onClickButton {
Write-Host "Click"
}
function onCloseButton {
closePort
unsubscribeFromPortEvents
$form.close()
}
##### PORT RELATED HELPERS
function createAndOpenPort {
param($portName = 'COM7', $baudRate = 9600)
$port = New-Object System.IO.Ports.SerialPort $portName,$baudRate,None,8,one
$port.open()
$port
}
function subscribeToPortEvents {
param($port)
Register-ObjectEvent -InputObject $port -EventName "DataReceived" -Action {
# $value = $Sender.ReadExisting()
$value = $Sender.ReadLine()
if ($value) {
Write-Host "GOT VALUE FROM READLINE: $value"
$global:latestPortMessage = $value.substring(0, $value.length - 2)
}
} | Out-Null
}
function unsubscribeFromPortEvents {
$subscribers = Get-EventSubscriber
$subscribers | foreach-object {
if ($_.SourceObject.GetType().FullName -eq "System.IO.Ports.SerialPort") {
Unregister-Event -SourceIdentifier $_.SourceIdentifier
}
}
}
function closePort {
try {
if ($port) {
if ($port.isOpen) {
$port.Close()
}
}
} catch {
logError $_
dumpError $_
}
}
. main
上安装了插件ERROR in ./src/pages/index.tsx
Module build failed (from ./node_modules/gatsby/dist/utils/babel-loader.js):
TypeError: Cannot read property 'type' of null
at VariableDeclarator (/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/babel-plugin-remove-graphql-queries/index.js:277:81)
at NodePath._call
(/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/@babel/traverse/lib/path/context.js:53:20)
at NodePath.call
(/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/@babel/traverse/lib/path/context.js:40:17)
at NodePath.visit
(/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/@babel/traverse/lib/path/context.js:88:12)
at TraversalContext.visitQueue
(/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/@babel/traverse/lib/context.js:118:16)
at TraversalContext.visitMultiple
(/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/@babel/traverse/lib/context.js:85:17)
at TraversalContext.visit
(/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/@babel/traverse/lib/context.js:144:19)
at Function.traverse.node
(/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/@babel/traverse/lib/index.js:94:17)
at NodePath.visit
(/mnt/d/Repositories/FnStacks/HandyTrade/handytrade-store-web/node_modules/@babel/traverse/lib/path/context.js:95:18)
at TraversalContext.visitQueue
ℹ ｢wdm｣: Failed to compile.
和所需的设置。我正在尝试在项目的起始页中读取siteMetadata对象。我尝试使用gatsby-plugin-ts-loader库中的gatsby-config.js和graphql，但失败了。这是我的前进方式
useStaticQuery这是我在gatsby-config.js中定义SiteMetada对象的方式
gatsby如果我删除所有读取siteMetadata的查询，则应用程序将正常运行。我正在Linux的Windows子系统上使用gatsby-Ubuntu 18.04.1
答案 0 :(得分：1)
当我在您的根目录中运行tsc -p .并检查输出时，我发现tsc将其编译：
const data = useStaticQuery(graphql`
query IndexQuery {
site {
siteMetadata {
title
}
}
}
`);
对此：
var data = useStaticQuery(graphql(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n query IndexQuery {\n site {\n siteMetadata {\n title\n }\n }\n }\n "], ["\n query IndexQuery {\n site {\n siteMetadata {\n title\n }\n }\n }\n "]))));
Gatsby期望graphql查询使用模板文字，但是tsc将其编译为常规函数。
要解决此问题，您需要将tsconfig更改为至少输出es6。
// tsconfig.json
{
compileOptions: {
"module": "esnext",
"target": "esnext", <-- or es6 & above
}
}
顺便说一句，我最近为gatsby发布了一个ts插件，旨在使在打字稿中使用gatsby尽可能流畅。它做的另一件事是自动为graphql查询生成类型。如果您尝试一下，不胜感激，请告诉我：