Node.js Azure Function 在 2022 年 4 月 26 日禁用将用户字段设置为 HTTP 请求对象

我在this PR中找到了罪魁祸首，它是为Azure Function runtime v4添加的.2.0.

The user field was added with only a getter.
We took the code and made the minimal example:

class Request {
    #cachedUser?: string | null;
    constructor() {
    }
    get user(): string | null {
        if (this.#cachedUser === undefined) {
            this.#cachedUser = "some value";
        }
        return this.#cachedUser;
    }
}

并得到了以下透明版本:

var __classPrivateFieldGet =
    (this && this.__classPrivateFieldGet) ||
    function (receiver, state, kind, f) {
        if (kind === 'a' && !f) throw new TypeError('Private accessor was defined without a getter')
        if (typeof state === 'function' ? receiver !== state || !f : !state.has(receiver))
            throw new TypeError('Cannot read private member from an object whose class did not declare it')
        return kind === 'm' ? f : kind === 'a' ? f.call(receiver) : f ? f.value : state.get(receiver)
    }
var __classPrivateFieldSet =
    (this && this.__classPrivateFieldSet) ||
    function (receiver, state, value, kind, f) {
        if (kind === 'm') throw new TypeError('Private method is not writable')
        if (kind === 'a' && !f) throw new TypeError('Private accessor was defined without a setter')
        if (typeof state === 'function' ? receiver !== state || !f : !state.has(receiver))
            throw new TypeError('Cannot write private member to an object whose class did not declare it')
        return kind === 'a' ? f.call(receiver, value) : f ? (f.value = value) : state.set(receiver, value), value
    }
var _Request_cachedUser
class Request {
    constructor() {
        _Request_cachedUser.set(this, void 0)
    }
    get user() {
        if (__classPrivateFieldGet(this, _Request_cachedUser, 'f') === undefined) {
            __classPrivateFieldSet(this, _Request_cachedUser, 'some value', 'f')
        }
        return __classPrivateFieldGet(this, _Request_cachedUser, 'f')
    }
}
_Request_cachedUser = new WeakMap()

// this section is added for testing
const request = new Request()
request.user = 'new value'
console.log(JSON.stringify(request.user))

因此，它总是返回初始值，在我们的示例中是"some value"，但在原始代码中只是undefined，不允许设置它.