如何使用jq为bundleDependencies数组添加元素时忽略重复项

问题场景 #

现有如下包配置JSON字符串：

json_string="$(cat <<'END'
{
  "name": "hello",
  "dependencies": {
    "progress": "^2.0.0",
    "tar": "^6.2.1"
  },
  "devDependencies": {
    "node-fetch": "~2.6.1",
    "yargs": "^16.2.0"
  }
}
END
)"

通过以下命令依次向bundleDependencies数组添加依赖键时：

# 添加dependencies的键到bundleDependencies
json_string="$(jq ".bundleDependencies += (.dependencies | keys)" <<< "$json_string")"
# 添加devDependencies的键到bundleDependencies
json_string="$(jq ".bundleDependencies += (.devDependencies | keys)" <<< "$json_string")"

重复执行添加devDependencies的命令，会导致数组中出现重复项：

jq ".bundleDependencies += (.devDependencies | keys)" <<< "$json_string"

输出结果：

{
  "name": "hello",
  "dependencies": {
    "progress": "^2.0.0",
    "tar": "^6.2.1"
  },
  "devDependencies": {
    "node-fetch": "~2.6.1",
    "yargs": "^16.2.0"
  },
  "bundleDependencies": [
    "progress",
    "tar",
    "node-fetch",
    "yargs",
    "node-fetch",
    "yargs"
  ]
}

解决方法 #

方法1：添加后自动去重 #

每次添加元素后，用unique过滤器对bundleDependencies数组去重，确保数组内元素唯一：

# 添加dependencies并去重
json_string="$(jq ".bundleDependencies += (.dependencies | keys) | .bundleDependencies |= unique" <<< "$json_string")"

# 添加devDependencies并去重
json_string="$(jq ".bundleDependencies += (.devDependencies | keys) | .bundleDependencies |= unique" <<< "$json_string")"

重复执行添加命令时，数组会自动去重，不会产生重复项。

方法2：一次性合并所有目标键并去重 #

如果无需分步添加，可直接合并dependencies和devDependencies的所有键，去重后赋值给bundleDependencies：

json_string="$(jq ".bundleDependencies = (.dependencies | keys) + (.devDependencies | keys) | .bundleDependencies |= unique" <<< "$json_string")"

方法3：精准添加不存在的元素 #

通过reduce遍历要添加的键，仅当元素不存在于数组中时才追加：

# 确保bundleDependencies存在（无则初始化为空数组），再添加devDependencies中未存在的键
json_string="$(jq '
  .bundleDependencies //= []
  | reduce (.devDependencies | keys[]) as $key (.;
    if .bundleDependencies | index($key) then . else .bundleDependencies += [$key] end
  )
' <<< "$json_string")"

内容的提问来源于stack exchange，提问作者stackbiz