move newline removal to comptime

src/main.zig

@@ -195,6 +195,19 @@ fn startRecirculation(allocator: std.mem.Allocator, id_token: []const u8, serial
     return result.status == .ok;
 }
 
+fn removeNewlines(comptime input: []const u8) []const u8 {
+    comptime {
+        var result: [input.len]u8 = undefined;
+        var i: usize = 0;
+        for (input) |c| {
+            result[i] = if (c == '\n') ' ' else c;
+            i += 1;
+        }
+        const final = result;
+        return &final;
+    }
+}
+
 /// Queries the device shadow to get current recirculation status
 fn getRecirculationStatus(allocator: std.mem.Allocator, id_token: []const u8, serial_number: []const u8) !json.Parsed(json.Value) {
     var client = http.Client{ .allocator = allocator };
@@ -213,17 +226,7 @@ fn getRecirculationStatus(allocator: std.mem.Allocator, id_token: []const u8, se
         \\}
     ;
 
-    var query_clean_buf: [query.len]u8 = undefined;
+    const query_clean = comptime removeNewlines(query);
-    // Remove newlines for JSON payload
-    const query_replacements = std.mem.replace(
-        u8,
-        query,
-        "\n",
-        " ",
-        query_clean_buf[0..],
-    );
-    const query_clean = query_clean_buf[0 .. query.len - ("\n".len * query_replacements)];
-
     const body = try std.fmt.allocPrint(allocator,
         \\{{"query":"{s}","variables":{{"heater_serial_number":"{s}"}}}}
     , .{ query_clean, serial_number });