fix: enable FileReader wpt and align to spec (#10063)

This adds some algorithms from the whatwg mimesniff, whatwg infra, and
whatwg encoding specs that FileReader needs to use internally.

1 files changed, 31 insertions, 0 deletions

diff --git a/op_crates/web/00_infra.js b/op_crates/web/00_infra.js
new file mode 100644
index 000000000..0590ffd03
--- /dev/null
+++ b/op_crates/web/00_infra.js
@@ -0,0 +1,31 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+// @ts-check
+/// <reference path="../../core/lib.deno_core.d.ts" />
+/// <reference path="../web/internal.d.ts" />
+/// <reference path="../web/lib.deno_web.d.ts" />
+
+"use strict";
+
+((window) => {
+  /**
+   * https://infra.spec.whatwg.org/#collect-a-sequence-of-code-points
+   * @param {string} input
+   * @param {number} position
+   * @param {(char: string) => boolean} condition
+   * @returns {{result: string, position: number}}
+   */
+  function collectSequenceOfCodepoints(input, position, condition) {
+    const start = position;
+    for (
+      let c = input.charAt(position);
+      position < input.length && condition(c);
+      c = input.charAt(++position)
+    );
+    return { result: input.slice(start, position), position };
+  }
+
+  window.__bootstrap.infra = {
+    collectSequenceOfCodepoints,
+  };
+})(globalThis);