Node.js solution for week 90/part 2

2 files changed, 49 insertions, 0 deletions

diff --git a/challenge-090/abigail/README.md b/challenge-090/abigail/README.md
index 546ac5f46d..c89a14792e 100644
--- a/challenge-090/abigail/README.md
+++ b/challenge-090/abigail/README.md
@@ -42,4 +42,5 @@ Write a script to demonstrate
 
 ## Solutions
 * [C](c/ch-2.c)
+* [Node.js](node/ch-2.js)
 * [Perl](perl/ch-2.pl)
diff --git a/challenge-090/abigail/node/ch-2.js b/challenge-090/abigail/node/ch-2.js
new file mode 100644
index 0000000000..4850a5f722
--- /dev/null
+++ b/challenge-090/abigail/node/ch-2.js
@@ -0,0 +1,48 @@
+let indent  = "                      ";
+let line    = indent . replace (/ /g, "-");
+let spacing = "  ";
+
+//
+// Read STDIN. Split on newlines, filter out empty lines,
+// split each line on white space, then call "show"
+//
+  require      ("fs")
+. readFileSync (0)               // Read all.
+. toString     ()                // Turn it into a string.
+. split        ("\n")            // Split on newlines.
+. filter       (_ => _ . length) // Filter out empty lines.
+. map          (_ => _ . split (/\s+/))
+. map          (_ => show (_ [0], _ [1]))
+;
+
+//
+// Return a number, padded with space to the required width.
+// If width is less than the length of n, bad things may happen.
+//
+function format_n (n, width) {
+//  return (indent + n) . substr (-width);
+    return ("                      " + n) . substr (-width);
+}
+
+//
+// Do the main work
+//
+function show (A, B) {
+    let P    = A * B;
+    let w_A  = ("" + A) . length;
+    let w_P  = ("" + P) . length;
+    let tick = String . fromCodePoint (0x2713);
+
+    while (A) {
+        process . stdout . write (format_n (A, w_A)   + spacing +
+                                  format_n (B, w_P)   + " "     +
+                                  (A % 2 ? tick : "") + "\n");
+        A = Math . floor (A / 2);
+        B = B * 2;
+    }
+
+    process . stdout . write (indent . substr (-w_A) + spacing +
+                              line   . substr (-w_P) + " +\n");
+    process . stdout . write (indent . substr (-w_A) + spacing +
+                                                  P  + "\n");
+}