fix: avoid deprecation message of abab package (#228)

Author: alexander-akait

package-lock.json

@@ -44,7 +44,6 @@
     "webpack": "^5.72.1"
   },
   "dependencies": {
-    "abab": "^2.0.6",
     "iconv-lite": "^0.6.3",
     "source-map-js": "^1.0.2"
   },

package.json

@@ -1,5 +1,3 @@
-import { atob } from "abab";
-
 const removeLeadingAndTrailingHTTPWhitespace = (string) =>
   string.replace(/^[ \t\n\r]+/, "").replace(/[ \t\n\r]+$/, "");
 
@@ -98,6 +96,117 @@ function percentDecodeBytes(input) {
   return output.slice(0, outputIndex);
 }
 
+/**
+ * A lookup table for atob(), which converts an ASCII character to the
+ * corresponding six-bit number.
+ */
+
+const characters =
+  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+function atobLookup(chr) {
+  const index = characters.indexOf(chr);
+  // Throw exception if character is not in the lookup string; should not be hit in tests
+  // eslint-disable-next-line no-undefined
+  return index < 0 ? undefined : index;
+}
+
+/**
+ * Implementation of atob() according to the HTML and Infra specs, except that
+ * instead of throwing INVALID_CHARACTER_ERR we return null.
+ */
+function atob(input) {
+  /* eslint-disable no-bitwise */
+  // Web IDL requires DOMStrings to just be converted using ECMAScript
+  // ToString, which in our case amounts to using a template literal.
+  let data = `${input}`;
+
+  // "Remove all ASCII whitespace from data."
+  data = data.replace(/[ \t\n\f\r]/g, "");
+
+  // "If data's length divides by 4 leaving no remainder, then: if data ends
+  // with one or two U+003D (=) code points, then remove them from data."
+  if (data.length % 4 === 0) {
+    data = data.replace(/==?$/, "");
+  }
+
+  // "If data's length divides by 4 leaving a remainder of 1, then return
+  // failure."
+  //
+  // "If data contains a code point that is not one of
+  //
+  // U+002B (+)
+  // U+002F (/)
+  // ASCII alphanumeric
+  //
+  // then return failure."
+  if (data.length % 4 === 1 || /[^+/0-9A-Za-z]/.test(data)) {
+    return null;
+  }
+
+  // "Let output be an empty byte sequence."
+  let output = "";
+
+  // "Let buffer be an empty buffer that can have bits appended to it."
+  //
+  // We append bits via left-shift and or.  accumulatedBits is used to track
+  // when we've gotten to 24 bits.
+  let buffer = 0;
+  let accumulatedBits = 0;
+
+  // "Let position be a position variable for data, initially pointing at the
+  // start of data."
+  //
+  // "While position does not point past the end of data:"
+  for (let i = 0; i < data.length; i++) {
+    // "Find the code point pointed to by position in the second column of
+    // Table 1: The Base 64 Alphabet of RFC 4648. Let n be the number given in
+    // the first cell of the same row.
+    //
+    // "Append to buffer the six bits corresponding to n, most significant bit
+    // first."
+    //
+    // atobLookup() implements the table from RFC 4648.
+    // eslint-disable-next-line no-bitwise
+    buffer <<= 6;
+
+    // eslint-disable-next-line no-bitwise
+    buffer |= atobLookup(data[i]);
+    accumulatedBits += 6;
+
+    // "If buffer has accumulated 24 bits, interpret them as three 8-bit
+    // big-endian numbers. Append three bytes with values equal to those
+    // numbers to output, in the same order, and then empty buffer."
+    if (accumulatedBits === 24) {
+      output += String.fromCharCode((buffer & 0xff0000) >> 16);
+      output += String.fromCharCode((buffer & 0xff00) >> 8);
+      output += String.fromCharCode(buffer & 0xff);
+      accumulatedBits = 0;
+      buffer = 0;
+    }
+    // "Advance position by 1."
+  }
+
+  // "If buffer is not empty, it contains either 12 or 18 bits. If it contains
+  // 12 bits, then discard the last four and interpret the remaining eight as
+  // an 8-bit big-endian number. If it contains 18 bits, then discard the last
+  // two and interpret the remaining 16 as two 8-bit big-endian numbers. Append
+  // the one or two bytes with values equal to those one or two numbers to
+  // output, in the same order."
+  if (accumulatedBits === 12) {
+    buffer >>= 4;
+    output += String.fromCharCode(buffer);
+  } else if (accumulatedBits === 18) {
+    buffer >>= 2;
+    output += String.fromCharCode((buffer & 0xff00) >> 8);
+    output += String.fromCharCode(buffer & 0xff);
+  }
+  /* eslint-enable no-bitwise */
+
+  // "Return output."
+  return output;
+}
+
 export default function parseDataUrl(stringInput) {
   let parsedUrl;