[firestore][js] start of blob support

lib/modules/firestore/Blob.js

@@ -0,0 +1,71 @@
+import Base64 from './utils/Base64';
+
+type BlobFormat = 'string' | 'array';
+
+export default class Blob {
+  constructor(data, type: BlobFormat) {
+    this._data = data;
+    this._type = type;
+  }
+
+  /**
+   * Creates a new Blob from the given Base64 string
+   * @url https://firebase.google.com/docs/reference/js/firebase.firestore.Blob#.fromBase64String
+   * @param base64 string
+   */
+  static fromBase64String(base64: string): Blob {
+    // TODO convert to Uint8Array?
+    return new Blob(base64, 'string');
+  }
+
+  /**
+   * Creates a new Blob from the given Uint8Array.
+   * @url https://firebase.google.com/docs/reference/js/firebase.firestore.Blob#.fromUint8Array
+   * @param array Array
+   */
+  static fromUint8Array(array: Array): Blob {
+    return new Blob(array, 'array');
+  }
+
+  /**
+   * Returns 'true' if this Blob is equal to the provided one.
+   * @url https://firebase.google.com/docs/reference/js/firebase.firestore.Blob#isEqual
+   * @param {*} blob Blob The Blob to compare against. Value must not be null.
+   * @returns boolean 'true' if this Blob is equal to the provided one.
+   */
+  isEqual(blob: Blob): boolean {
+    // TODO comparison checks
+    console.log(blob);
+    return true;
+  }
+
+  /**
+   * Returns the bytes of a Blob as a Base64-encoded string.
+   * @url https://firebase.google.com/docs/reference/js/firebase.firestore.Blob#toBase64
+   * @returns string The Base64-encoded string created from the Blob object.
+   */
+  toBase64(): string {
+    if (this._type === 'string') return this._data;
+
+    let binary = '';
+    const len = this._data.byteLength;
+    for (let i = 0; i < len; i++) {
+      binary += String.fromCharCode(this._data[i]);
+    }
+
+    return Base64.btoa(binary);
+  }
+
+  /**
+   * Returns the bytes of a Blob in a new Uint8Array.
+   * @url https://firebase.google.com/docs/reference/js/firebase.firestore.Blob#toUint8Array
+   * @returns non-null Uint8Array The Uint8Array created from the Blob object.
+   */
+  toUint8Array(): Uint8Array {
+    if (this._type === 'array') return this._data;
+    // TODO conversion
+    // TODO conversion
+    // TODO conversion
+    return new Uint8Array();
+  }
+}

lib/modules/firestore/utils/Base64.js

@@ -0,0 +1,68 @@
+// @flow
+/* eslint-disable */
+
+const CHARS =
+  'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
+
+export default {
+  /**
+   * window.btoa
+   */
+  btoa(input: string = ''): string {
+    let map;
+    let i = 0;
+    let block = 0;
+    let output = '';
+
+    // eslint-disable-next-line
+    for (
+      block = 0, i = 0, map = CHARS;
+      input.charAt(i | 0) || ((map = '='), i % 1);
+      output += map.charAt(63 & (block >> (8 - (i % 1) * 8)))
+    ) {
+      const charCode = input.charCodeAt((i += 3 / 4));
+
+      if (charCode > 0xff) {
+        throw new Error(
+          "'btoa' failed: The string to be encoded contains characters outside of the Latin1 range."
+        );
+      }
+
+      block = (block << 8) | charCode;
+    }
+
+    return output;
+  },
+
+  /**
+   * window.atob
+   */
+  atob(input: string = ''): string {
+    let i = 0;
+    let bc = 0;
+    let bs = 0;
+    let buffer;
+    let output = '';
+
+    const str = input.replace(/=+$/, '');
+
+    if (str.length % 4 === 1) {
+      throw new Error(
+        "'atob' failed: The string to be decoded is not correctly encoded."
+      );
+    }
+
+    // eslint-disable-next-line
+    for (
+      bc = 0, bs = 0, i = 0;
+      (buffer = str.charAt(i++));
+      ~buffer && ((bs = bc % 4 ? bs * 64 + buffer : buffer), bc++ % 4)
+        ? (output += String.fromCharCode(255 & (bs >> ((-2 * bc) & 6))))
+        : 0
+    ) {
+      buffer = CHARS.indexOf(buffer);
+    }
+
+    return output;
+  },
+};