角度6类型错误：无法读取未定义的属性（读取“长度”）错误

Question

createToken() {
    this._tokenService
        .getAuth(this.userId, this.token)
        .subscribe(res => 
        {}, 
        error => {
            console.log(error);
        });
    }

    getAuth(upn, token) {
        var param = {
            Upn: upn,
            Token: token
        };

        console.log(param);
        
        return this._http.post(
            this.REST_API_ADDR + "auth", 
            param, 
            this.getAuthRequestHeader()
        );
    }

    getAuthRequestHeader() {
        console.log("header");

        const authHeaders = new HttpHeaders({
            'Content-Type':'application/json',
        });

        return { headers: authHeaders };
    }

尝试使用< code>getAuth请求来存储令牌。请求不调用API并抛出错误。

TypeError:无法在HttpHeaders.push处读取undefined的属性(读取“length”)../node _ modules/@ angular/common/Fe sm5/http . js . http headers . apply update(http . js:199)at http . js:170 at array . foreach()at http headers . push..HttpHeaders.push上的/node _ modules/@ angular/common/Fe sm5/http . js . http headers . init(http . js:170)../node _ modules/@ angular/common/Fe sm5/http . js . http headers . foreach(http . js:235)at Observable。_subscribe (http.js:1435)在Observable.push../node _ modules/rxjs/_ es M5/internal/observable . js . observable . _ try subscribe(observable . js:42)at observable . push../node _ modules/rxjs/_ es M5/internal/observable . js . observable . subscribe(observable . js:28)在MapOperator.push../node _ modules/rxjs/_ es M5/internal/operators/map . js . map operator . call(map . js:18)at observable . push../node _ modules/rxjs/_ es M5/internal/observable . js . observable . subscribe(observable . js:23)

你能告诉我当这个错误发生时检查哪个部分吗？另外，如果你知道错误的原因以及如何解决，请告诉我。

Answer 1

此处描述并解决了该错误：https://github.com/angular/angular/issues/18743#issuecomment-367742057

基本上，你的头有未定义/空值。您应该检查传递给请求的header-option。