Fix.

node_modules/abab/lib/atob.js

@@ -0,0 +1,107 @@
+"use strict";
+
+/**
+ * Implementation of atob() according to the HTML and Infra specs, except that
+ * instead of throwing INVALID_CHARACTER_ERR we return null.
+ */
+function atob(data) {
+  // Web IDL requires DOMStrings to just be converted using ECMAScript
+  // ToString, which in our case amounts to using a template literal.
+  data = `${data}`;
+  // "Remove all ASCII whitespace from data."
+  data = data.replace(/[ \t\n\f\r]/g, "");
+  // "If data's length divides by 4 leaving no remainder, then: if data ends
+  // with one or two U+003D (=) code points, then remove them from data."
+  if (data.length % 4 === 0) {
+    data = data.replace(/==?$/, "");
+  }
+  // "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.
+    buffer <<= 6;
+    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);
+      buffer = accumulatedBits = 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);
+  }
+  // "Return output."
+  return output;
+}
+/**
+ * A lookup table for atob(), which converts an ASCII character to the
+ * corresponding six-bit number.
+ */
+function atobLookup(chr) {
+  if (/[A-Z]/.test(chr)) {
+    return chr.charCodeAt(0) - "A".charCodeAt(0);
+  }
+  if (/[a-z]/.test(chr)) {
+    return chr.charCodeAt(0) - "a".charCodeAt(0) + 26;
+  }
+  if (/[0-9]/.test(chr)) {
+    return chr.charCodeAt(0) - "0".charCodeAt(0) + 52;
+  }
+  if (chr === "+") {
+    return 62;
+  }
+  if (chr === "/") {
+    return 63;
+  }
+  // Throw exception; should not be hit in tests
+  return undefined;
+}
+
+module.exports = atob;