reader = new plus.io.FileReader()编译报错

[HBuilder] 16:06:42.943 ERROR in /Users/taylor/Project/app/src/app.ts(415,34):
[HBuilder] 16:06:42.946 415:34 This expression is not constructable.
[HBuilder] 16:06:42.946 Type 'PlusIoFileReader' has no construct signatures.
[HBuilder] 16:06:42.951 413 | // 文件系统中的读取文件对象，用于获取文件的内容
[HBuilder] 16:06:42.953 414 | try {
[HBuilder] 16:06:42.954 > 415 | reader = new plus.io.FileReader(); // new一个可以用来读取文件的对象fileReader
[HBuilder] 16:06:42.958 | ^
[HBuilder] 16:06:42.960 416 | } catch (error) {
[HBuilder] 16:06:42.963 417 | uni.showToast({
[HBuilder] 16:06:42.966 418 | title: "读取失败",
[HBuilder] 16:06:43.076 项目 'app' 编译成功。
[HBuilder] 16:06:43.080 ERROR in /Users/taylor/Project/app/src/app.ts(415,34):
[HBuilder] 16:06:43.081 415:34 This expression is not constructable.
[HBuilder] 16:06:43.084 Type 'PlusIoFileReader' has no construct signatures.
[HBuilder] 16:06:43.088 413 | // 文件系统中的读取文件对象，用于获取文件的内容
[HBuilder] 16:06:43.091 414 | try {
[HBuilder] 16:06:43.092 > 415 | reader = new plus.io.FileReader(); // new一个可以用来读取文件的对象fileReader
[HBuilder] 16:06:43.095 | ^
[HBuilder] 16:06:43.099 416 | } catch (error) {
[HBuilder] 16:06:43.103 417 | uni.showToast({
[HBuilder] 16:06:43.103 418 | title: "读取失败",
[HBuilder] 16:06:43.108 ERROR Build failed with errors.
[HBuilder] 16:06:43.144 项目 'app'导出失败