PowerShell中ConvertFrom-Json转换嵌套对象为空的解决方法

问题场景 #

使用PowerShell 7.2.5的ConvertFrom-Json命令解析项目的package.json文件时，发现转换后的对象中嵌套属性（如scripts、dependencies、devDependencies）在Write-Host输出时显示为空，但实际需要修改顶层属性（如releaseDate）并保存回文件。

原始JSON文件（package.json） #

{
  "name": "demo",
  "displayName": "Demo",
  "version": "0.2.58",
  "releaseDate": "yesterday",
  "private": true,
  "scripts": {
    "start": "vue-cli-service serve",
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "lint": "vue-cli-service lint"
  },
  "dependencies": {
    "bootstrap": "^5.1.3",
    "core-js": "^3.6.5",
    "exifreader": "^3.14.1",
    "file-saver": "^2.0.5",
    "vue-flux": "^6.4.0",
    "vue-i18n": "^9.2.0-beta.23",
    "vue-router": "^4.0.0-0",
    "vuex": "^4.0.0-0"
  },
  "devDependencies": {
    "@types/file-saver": "^2.0.5",
    "@typescript-eslint/eslint-plugin": "^4.18.0",
    "@typescript-eslint/parser": "^4.18.0",
    "@vue/cli-plugin-babel": "~4.5.0",
    "@vue/cli-plugin-eslint": "~4.5.0",
    "@vue/cli-plugin-router": "~4.5.0",
    "@vue/cli-plugin-typescript": "~4.5.0",
    "@vue/cli-plugin-vuex": "~4.5.0",
    "@vue/cli-service": "~4.5.0",
    "@vue/compiler-sfc": "^3.0.0",
    "@vue/eslint-config-prettier": "^6.0.0",
    "@vue/eslint-config-typescript": "^7.0.0",
    "eslint": "^6.7.2",
    "eslint-plugin-prettier": "^3.3.1",
    "eslint-plugin-vue": "^7.0.0",
    "prettier": "^2.2.1",
    "sass": "^1.44.0",
    "sass-loader": "^10.2.0",
    "typescript": "~4.1.5"
  }
}

原始脚本及问题输出 #

原始脚本：

$Path = "./package.json"

$Content = (Get-Content $Path ) | ConvertFrom-Json 
Write-Host $Content

$Content.releaseDate = "today"
Write-Host $Content

运行后输出：

@{name=demo; displayName=Demo; version=0.2.58; releaseDate=yesterday; private=True; scripts=; dependencies=; devDependencies=}
@{name=demo; displayName=Demo; version=0.2.58; releaseDate=today; private=True; scripts=; dependencies=; devDependencies=}

原因解析 #

Write-Host直接输出对象时，会采用简洁格式展示，仅显示顶层的简单属性，嵌套的复杂对象（如JSON中的子对象）会被简化为空白，并非对象本身丢失。实际上ConvertFrom-Json已经完整解析了所有嵌套内容，只是输出方式导致看起来为空。

解决方案 #

1. 正确查看解析后的对象 #

如果需要验证嵌套属性是否存在，不要用Write-Host直接输出整个对象，改用以下方式：

• 将对象转回JSON格式查看：$Content | ConvertTo-Json -Depth 10（-Depth指定嵌套层级，避免截断）
• 单独访问嵌套属性：Write-Host $Content.scripts 或 Write-Host $Content.dependencies.bootstrap

2. 修改并保存回文件 #

修改属性后，使用ConvertTo-Json将对象转回JSON并写入文件，确保所有嵌套内容被保留：

$Path = "./package.json"

# 读取并解析JSON（-Raw参数确保一次性读取完整内容，避免换行符干扰）
$Content = Get-Content $Path -Raw | ConvertFrom-Json

# 修改目标属性
$Content.releaseDate = "today"

# 将修改后的对象转回JSON并保存（-Depth确保嵌套内容完整输出）
$Content | ConvertTo-Json -Depth 10 | Set-Content $Path -Force

# 验证结果（输出完整JSON）
$Content | ConvertTo-Json -Depth 10

验证结果 #

运行修改后的脚本后，输出的完整JSON会包含所有嵌套属性，且releaseDate已更新为today：

{
  "name": "demo",
  "displayName": "Demo",
  "version": "0.2.58",
  "releaseDate": "today",
  "private": true,
  "scripts": {
    "start": "vue-cli-service serve",
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "lint": "vue-cli-service lint"
  },
  "dependencies": {
    "bootstrap": "^5.1.3",
    "core-js": "^3.6.5",
    "exifreader": "^3.14.1",
    "file-saver": "^2.0.5",
    "vue-flux": "^6.4.0",
    "vue-i18n": "^9.2.0-beta.23",
    "vue-router": "^4.0.0-0",
    "vuex": "^4.0.0-0"
  },
  "devDependencies": {
    "@types/file-saver": "^2.0.5",
    "@typescript-eslint/eslint-plugin": "^4.18.0",
    "@typescript-eslint/parser": "^4.18.0",
    "@vue/cli-plugin-babel": "~4.5.0",
    "@vue/cli-plugin-eslint": "~4.5.0",
    "@vue/cli-plugin-router": "~4.5.0",
    "@vue/cli-plugin-typescript": "~4.5.0",
    "@vue/cli-plugin-vuex": "~4.5.0",
    "@vue/cli-service": "~4.5.0",
    "@vue/compiler-sfc": "^3.0.0",
    "@vue/eslint-config-prettier": "^6.0.0",
    "@vue/eslint-config-typescript": "^7.0.0",
    "eslint": "^6.7.2",
    "eslint-plugin-prettier": "^3.3.1",
    "eslint-plugin-vue": "^7.0.0",
    "prettier": "^2.2.1",
    "sass": "^1.44.0",
    "sass-loader": "^10.2.0",
    "typescript": "~4.1.5"
  }
}

内容的提问来源于stack exchange，提问作者Gert Rikkers