basic-fetch.ts

export enum FetchType {
    GET = "GET",
    POST = "POST",
    PUT = "PUT",
    DELETE = "DELETE",
    PATCH = "PATCH"
}

// error logic faulty => does both, error & not error if both are provided
export function jsonFetchWrapper(url: string, fetchType: FetchType, onResult?: (result: any) => void, body?: BodyInit, headers?: any, onError?: (response: any) => void) {
    if (!headers) headers = {};
    headers["Content-Type"] = "application/json";

    let hasError = false;
    let myFetch = fetch(url, {
        method: fetchType,
        headers: headers,
        body: body,
    }).then(response => {

        if (!response.ok) {
            if (onError) onError(response);
            else throw new Error("Error in request at " + url);
            hasError = true;
        }
        else {
            const contentType = response.headers.get("content-type");
            if (contentType && contentType.indexOf("application/json") !== -1) return response.json();
            else return response.text();
        }
    }, (error) => {
        console.log("Error in request at " + url);
    });

    if (onResult && !hasError) myFetch.then(result => onResult(result));


}

//runs either onError or onResult, not both
export function jsonFetchWrapperEitherOr(url: string, fetchType: FetchType, onResult?: (result: any) => void, body?: BodyInit, headers?: any, onError?: (response: any) => void) {
    if (!headers) headers = {};
    headers["Content-Type"] = "application/json";

    const finalOnError = onError ? onError : ((response: any) => { throw new Error("Error in request at " + url) });
    fetch(url, {
        method: fetchType,
        headers: headers,
        body: body,
    }).then(response => {
        if (!response.ok) return response.text().then((text) => finalOnError(text));
        else return response.json().then((json) => onResult(json));
    }, (error) => {
        console.log("Error in request at " + url);
    });
}

export function textFetchWrapper(url: string, fetchType: FetchType, onResult?: (result: any) => void, body?: BodyInit, headers?: any) {
    if (!headers) headers = {};
    headers["Content-Type"] = "application/json";

    let myFetch: any = fetch(url, {
        method: fetchType,
        headers: headers,
        body: body,
    })
        .then(response => {
            if (!response.ok) {
                throw new Error(response.statusText);
            }
            return response.text();
        });
    if (onResult) myFetch = myFetch.then((result: any) => onResult(result));
}