🆕 Added support for JSON5

packages/utils/src/JsonParser.ts

@@ -0,0 +1,88 @@
+import JSON5 from 'json5';
+
+const JSON5_EXTENSION = /\.json5(?:[?#]|$)/i;
+const JSON5_MIME = /(?:application|text)\/(?:json5|x-json5)/i;
+
+const looksLikeJson5Url = (url: string): boolean => !!url && JSON5_EXTENSION.test(url);
+
+const looksLikeJson5ContentType = (contentType: string): boolean => !!contentType && JSON5_MIME.test(contentType);
+
+const formatParseError = (sourceUrl: string, strictError: unknown, json5Error: unknown): string =>
+{
+    const strictMessage = (strictError as Error)?.message || String(strictError);
+    const json5Message = (json5Error as Error)?.message || String(json5Error);
+    const source = sourceUrl ? ` in "${ sourceUrl }"` : '';
+
+    if(strictMessage === json5Message) return `Failed to parse JSON/JSON5${ source } — ${ json5Message }`;
+
+    return `Failed to parse JSON/JSON5${ source } — JSON5: ${ json5Message } (strict JSON: ${ strictMessage })`;
+};
+
+export const parseConfigJson = <T = any>(text: string, sourceUrl: string = ''): T =>
+{
+    if(text === null || text === undefined) throw new Error(`Empty response${ sourceUrl ? ` for "${ sourceUrl }"` : '' }`);
+
+    const trimmed = text.length > 0 ? text : '';
+
+    if(looksLikeJson5Url(sourceUrl))
+    {
+        try
+        {
+            return JSON5.parse<T>(trimmed);
+        }
+        catch(err)
+        {
+            throw new Error(formatParseError(sourceUrl, err, err));
+        }
+    }
+
+    let strictError: unknown;
+
+    try
+    {
+        return JSON.parse(trimmed) as T;
+    }
+    catch(err)
+    {
+        strictError = err;
+    }
+
+    try
+    {
+        return JSON5.parse<T>(trimmed);
+    }
+    catch(json5Error)
+    {
+        throw new Error(formatParseError(sourceUrl, strictError, json5Error));
+    }
+};
+
+export const parseConfigJsonFromResponse = async <T = any>(response: Response, sourceUrl: string = ''): Promise<T> =>
+{
+    const contentType = response.headers?.get?.('content-type') || '';
+    const text = await response.text();
+    const url = sourceUrl || (response as any).url || '';
+
+    if(looksLikeJson5ContentType(contentType) && !looksLikeJson5Url(url))
+    {
+        try
+        {
+            return JSON5.parse<T>(text);
+        }
+        catch(err)
+        {
+            throw new Error(formatParseError(url, err, err));
+        }
+    }
+
+    return parseConfigJson<T>(text, url);
+};
+
+export const fetchConfigJson = async <T = any>(url: string, init?: RequestInit): Promise<T> =>
+{
+    const response = await fetch(url, init);
+
+    if(!response || response.status !== 200) throw new Error(`Failed to fetch "${ url }" — server returned HTTP ${ response?.status ?? 'no response' }`);
+
+    return parseConfigJsonFromResponse<T>(response, url);
+};