JavaScript solution for week 84, part 1.

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diff --git a/challenge-084/abigail/node/ch-1.js b/challenge-084/abigail/node/ch-1.js
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+//
+// You are given an integer $N.
+//
+// Write a script to reverse the given integer and print the result.
+// Print 0 if the result doesn't fit in 32-bit signed integer.
+// 
+// The number 2,147,483,647 is the maximum positive value for a 32-bit
+// signed binary integer in computing.
+// 
+
+//
+// Note that the largest *positive* value which can fit in a
+// 32 bit integer is 2,147,483,647, but the largest *negative*
+// value is -2,147,483,648.
+//
+
+//
+// Create an interface to read from STDIN
+//
+const rl = require ('readline') . createInterface ({
+    input:  process . stdin,
+});
+ 
+//
+// Read lines of input, calculate the result, and print it.
+// 
+rl . on ('line', (line) => {
+    console . log (do_reverse (line));
+});
+
+
+function do_reverse (line) {
+    let sign = "";
+    //
+    // Strip off a leading hyphen; remember if we did so.
+    //
+    if (line . substring (0, 1) == "-") {
+        line = line . substring (1);
+        sign = "-";
+    }
+
+    //
+    // Reverse the digits.
+    //
+    let enil = sign + line . split ("") . reverse () . join ("");
+
+    //
+    // Turn the result into a bigint, so we can safely treat it
+    // as a number.
+    //
+    let result = BigInt (enil);
+
+    //
+    // If the result is too large (or too small), return 0.
+    // Else, return elin. Note that we should not return result;
+    // since result is a BigInt, printing it adds a trailing 'n'.
+    //
+    return result > 2147483647 || result < -2147483648 ? 0 : enil;
+}