When dealing with very large numbers (>= 1e+21), result in the send() method fails to convert scientific notation to a number, creating downstream BigNumber conversion errors

FromExponential.js

@@ -0,0 +1,33 @@
+// src: https://gist.github.com/jiggzson/b5f489af9ad931e3d186
+const SCIENTIFIC_NUMBER_REGEX = /\d+\.?\d*e[\+\-]*\d+/i;
+
+// Convert from scientific notation into a number
+// e.g. from 9.99998934104e+21 to 9999989341040000000000
+const scientificToDecimal = function(number) {
+    let numberHasSign = number.startsWith("-") || number.startsWith("+");
+    let sign = numberHasSign ? number[0] : "";
+    number = numberHasSign ? number.replace(sign, "") : number;
+
+    //if the number is in scientific notation remove it
+    if (SCIENTIFIC_NUMBER_REGEX.test(number)) {
+        let zero = '0';
+        let parts = String(number).toLowerCase().split('e'); //split into coeff and exponent
+        let e = parts.pop();//store the exponential part
+        let l = Math.abs(e); //get the number of zeros
+        let sign = e / l;
+        let coeff_array = parts[0].split('.');
+
+        if (sign === -1) {
+            coeff_array[0] = Math.abs(coeff_array[0]);
+            number = zero + '.' + new Array(l).join(zero) + coeff_array.join('');
+        } else {
+            let dec = coeff_array[1];
+            if (dec) l = l - dec.length;
+            number = coeff_array.join('') + new Array(l + 1).join(zero);
+        }
+    }
+
+    return `${sign}${number}`;
+};
+
+module.exports = scientificToDecimal;

RemoteMetaMaskProvider.js

@@ -1,3 +1,5 @@
+const fromExponential = require('./FromExponential');
+
 class RemoteMetaMaskProvider {
   constructor(connector) {
     this._connector = connector;
@@ -74,6 +76,13 @@ class RemoteMetaMaskProvider {
     // Format for "eth_filter"
     if (result && result.logIndex) return [result];
 
+    // If result is in scientific notation,
+    // then convert it into number form so that it can be used by ethers' bignumber type
+    // e.g. from 9.99862115952e+21 to 9998621159520000000000
+    if (result && !isNaN(result) && (typeof result === 'string') && (!result.startsWith('0x'))) {
+      return fromExponential(result);
+    }
+
     return result;
   }