Typescript stuff.

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/vector/getconfig.ts

@@ -0,0 +1,73 @@
+/*
+Copyright 2018 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import request from 'browser-request';
+
+// Load the config file. First try to load up a domain-specific config of the
+// form "config.$domain.json" and if that fails, fall back to config.json.
+export async function getVectorConfig(relativeLocation: string='') {
+    if (relativeLocation !== '' && !relativeLocation.endsWith('/')) relativeLocation += '/';
+
+    const specificConfigPromise = getConfig(`${relativeLocation}config.${document.domain}.json`);
+    const generalConfigPromise = getConfig(relativeLocation + "config.json");
+
+    try {
+        const configJson = await specificConfigPromise;
+        // 404s succeed with an empty json config, so check that there are keys
+        if (Object.keys(configJson).length === 0) {
+            throw new Error(); // throw to enter the catch
+        }
+        return configJson;
+    } catch (e) {
+        return await generalConfigPromise;
+    }
+}
+
+function getConfig(configJsonFilename: string): Promise<{}> {
+    return new Promise(function(resolve, reject) {
+        request(
+            { method: "GET", url: configJsonFilename, qs: { cachebuster: Date.now() } },
+            (err, response, body) => {
+                try {
+                    if (err || response.status < 200 || response.status >= 300) {
+                        // Lack of a config isn't an error, we should
+                        // just use the defaults.
+                        // Also treat a blank config as no config, assuming
+                        // the status code is 0, because we don't get 404s
+                        // from file: URIs so this is the only way we can
+                        // not fail if the file doesn't exist when loading
+                        // from a file:// URI.
+                        if (response) {
+                            if (response.status == 404 || (response.status == 0 && body == '')) {
+                                resolve({});
+                            }
+                        }
+                        reject({err: err, response: response});
+                        return;
+                    }
+
+                    // We parse the JSON ourselves rather than use the JSON
+                    // parameter, since this throws a parse error on empty
+                    // which breaks if there's no config.json and we're
+                    // loading from the filesystem (see above).
+                    resolve(JSON.parse(body));
+                } catch (e) {
+                    reject({err: e});
+                }
+            },
+        );
+    });
+}