has-private-fields:确定JS环境是否具有私有字段（“ class {#x;}”）支持

有私人领域 确定JS环境是否具有私有字段（ class { #x; } ）支持。 例子 const assert = require ( 'assert' ) ; const hasPrivateFields = require ( 'has-private-fields' ) ; assert . equal ( hasPrivateFields ( ) , true ) ; // if the environment has native class private fields support (node v12+) const { hasPrivateAccessors , hasPrivateMethods } = hasPrivateFields ; assert . equal ( hasPrivateAccessors ( ) , true ) ; // if the e