feat(urbex): added headers class to parse and manipulate config headers

lib/core/headers.ts

@@ -0,0 +1,139 @@
+import {
+    isArray,
+    isObject,
+    isUndefined,
+    hasOwnProperty,
+    forEach,
+    deepMerge,
+    capitalize
+} from "../utils";
+import { debug } from "../debug";
+
+type UrbexHeaderValues = string | number | boolean | null | undefined;
+type ObjectHeaders = Record<string, UrbexHeaderValues>;
+type ArrayHeaders = Array<[string, UrbexHeaderValues]>;
+
+export type BaseUrbexHeaders = ObjectHeaders;
+
+const DefaultHeaders = {
+    "Content-Type": "application/json"
+};
+
+function parseHeaderKey(key: string): string {
+    if (key) {
+        return formatHeaderKey(key.toLowerCase()).trim();
+    }
+
+    return undefined;
+}
+
+function parseHeaderValue(value: UrbexHeaderValues): string {
+    if (isUndefined(value) || value === false || value === null) {
+        return undefined;
+    }
+
+    if (isArray(value)) {
+        return value.join(", ");
+    }
+
+    if (isObject(value)) {
+        return JSON.stringify(value);
+    }
+
+    return String(value);
+}
+
+function normalizeHeaders(headers: BaseUrbexHeaders): ObjectHeaders {
+    const newHeaders: BaseUrbexHeaders = {};
+
+    forEach(headers, (key, value) => {
+        if (isUndefined(key) || isUndefined(value)) {
+            return;
+        }
+
+        const normalizedKey = parseHeaderKey(key);
+        const normalizedValue = parseHeaderValue(value);
+
+        if (normalizedKey && normalizedValue) {
+            newHeaders[normalizedKey] = normalizedValue;
+        }
+    });
+
+    return newHeaders;
+}
+
+function formatHeaderKey(key: string): string {
+    if (isUndefined(key)) {
+        return undefined;
+    }
+
+    return key.split("-").map(capitalize).join("-");
+}
+
+export class UrbexHeaders {
+    protected $headers: BaseUrbexHeaders = {};
+
+    constructor() {
+        this.set(DefaultHeaders);
+    }
+
+    get defaults(): typeof DefaultHeaders {
+        return DefaultHeaders;
+    }
+
+    /**
+     * Set a header configuration to use for all requests made by the current
+     * instance of the Urbex client
+     *
+     * Setting a configuration will merge with any existing configuration.
+     * Optionally, you can pass a boolean to clear the existing configuration
+     *
+     * @param headers The headers to set
+     * @param merge Whether to merge the headers with the existing configuration
+     */
+    set(headers?: BaseUrbexHeaders, merge: boolean = true): BaseUrbexHeaders {
+        if (!isObject(headers)) {
+            debug(
+                "error",
+                `Attempted to set headers with a non-object value: ${typeof headers}`
+            );
+            return headers;
+        }
+
+        const normalizedHeaders = normalizeHeaders(headers);
+        const merged = merge
+            ? deepMerge(this.$headers, normalizedHeaders)
+            : normalizedHeaders;
+
+        return (this.$headers = merged);
+    }
+    /**
+     * Get the current headers object
+     */
+    get(): BaseUrbexHeaders {
+        return this.$headers;
+    }
+    /**
+     * Delete a header from the headers object
+     */
+    delete(key: string): void {
+        forEach(this.$headers, (headerKey) => {
+            if (headerKey.toLowerCase() === key.toLowerCase()) {
+                delete this.$headers[headerKey];
+            }
+        });
+    }
+    /**
+     *
+     * Clear all headers that have been set
+     * @param empty Whether to empty the headers object
+     *
+     */
+    clear(empty: boolean = false): void {
+        this.$headers = {};
+
+        if (!empty) {
+            this.set(DefaultHeaders);
+        }
+    }
+}