Move fetch headers into its own file.

1 files changed, 85 insertions, 0 deletions

diff --git a/js/headers.ts b/js/headers.ts
new file mode 100644
index 000000000..6892b0ef2
--- /dev/null
+++ b/js/headers.ts
@@ -0,0 +1,85 @@
+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+import * as domTypes from "./dom_types";
+import { DomIterableMixin } from "./mixins/dom_iterable";
+
+// tslint:disable-next-line:no-any
+function isHeaders(value: any): value is domTypes.Headers {
+  return value instanceof Headers;
+}
+
+const headerMap = Symbol("header map");
+
+// ref: https://fetch.spec.whatwg.org/#dom-headers
+class HeadersBase {
+  private [headerMap]: Map<string, string>;
+
+  private _normalizeParams(name: string, value?: string): string[] {
+    name = String(name).toLowerCase();
+    value = String(value).trim();
+    return [name, value];
+  }
+
+  constructor(init?: domTypes.HeadersInit) {
+    if (init === null) {
+      throw new TypeError(
+        "Failed to construct 'Headers'; The provided value was not valid"
+      );
+    } else if (isHeaders(init)) {
+      this[headerMap] = new Map(init);
+    } else {
+      this[headerMap] = new Map();
+      if (Array.isArray(init)) {
+        for (const [rawName, rawValue] of init) {
+          const [name, value] = this._normalizeParams(rawName, rawValue);
+          const existingValue = this[headerMap].get(name);
+          this[headerMap].set(
+            name,
+            existingValue ? `${existingValue}, ${value}` : value
+          );
+        }
+      } else if (init) {
+        const names = Object.keys(init);
+        for (const rawName of names) {
+          const rawValue = init[rawName];
+          const [name, value] = this._normalizeParams(rawName, rawValue);
+          this[headerMap].set(name, value);
+        }
+      }
+    }
+  }
+
+  append(name: string, value: string): void {
+    const [newname, newvalue] = this._normalizeParams(name, value);
+    const v = this[headerMap].get(newname);
+    const str = v ? `${v}, ${newvalue}` : newvalue;
+    this[headerMap].set(newname, str);
+  }
+
+  delete(name: string): void {
+    const [newname] = this._normalizeParams(name);
+    this[headerMap].delete(newname);
+  }
+
+  get(name: string): string | null {
+    const [newname] = this._normalizeParams(name);
+    const value = this[headerMap].get(newname);
+    return value || null;
+  }
+
+  has(name: string): boolean {
+    const [newname] = this._normalizeParams(name);
+    return this[headerMap].has(newname);
+  }
+
+  set(name: string, value: string): void {
+    const [newname, newvalue] = this._normalizeParams(name, value);
+    this[headerMap].set(newname, newvalue);
+  }
+}
+
+// @internal
+// tslint:disable-next-line:variable-name
+export const Headers = DomIterableMixin<string, string, typeof HeadersBase>(
+  HeadersBase,
+  headerMap
+);