Add log method for printing multiline text above a spinner (ref #36 & #…

…43)

lib/tty/spinner.rb

@@ -350,23 +350,31 @@ def kill
     #
     # @api public
     def spin
+      return if done?
+
       synchronize do
-        return if @done
         emit(:spin)
-
-        if @hide_cursor && !spinning?
-          write(TTY::Cursor.hide)
-        end
-
-        data = message.gsub(MATCHER, @frames[@current])
-        data = replace_tokens(data)
-        write(data, true)
+        render
         @current = (@current + 1) % @length
         @state = :spinning
-        data
       end
     end
 
+    # Render spinner to the output
+    #
+    # @api private
+    def render
+      return if done?
+
+      if @hide_cursor && !spinning?
+        write(TTY::Cursor.hide)
+      end
+
+      data = message.gsub(MATCHER, @frames[@current])
+      data = replace_tokens(data)
+      write(data, true)
+    end
+
     # Redraw the indent for this spinner, if it exists
     #
     # @api private
@@ -474,6 +482,23 @@ def update(tokens)
       end
     end
 
+    # Log text above the current spinner
+    #
+    # @param [String] text
+    #   the message to log out
+    #
+    # @api public
+    def log(text)
+      synchronize do
+        cleared_text = text.to_s.lines.map do |line|
+          TTY::Cursor.clear_line + line
+        end.join
+
+        write("#{cleared_text}#{"\n" unless cleared_text.end_with?("\n")}", false)
+        render
+      end
+    end
+
     # Check if IO is attached to a terminal
     #
     # return [Boolean]

spec/unit/log_spec.rb

@@ -0,0 +1,60 @@
+RSpec.describe TTY::Spinner, "#log" do
+  let(:output) { StringIO.new('', 'w+') }
+
+  it "logs a message above a spinner" do
+    spinner = TTY::Spinner.new(output: output)
+
+    2.times {
+      spinner.log "foo\nbar"
+      spinner.spin
+    }
+    output.rewind
+
+    expect(output.read).to eq([
+      "\e[2K\e[1Gfoo\n",
+      "\e[2K\e[1Gbar\n",
+      "\e[1G|",
+      "\e[1G|",
+      "\e[2K\e[1Gfoo\n",
+      "\e[2K\e[1Gbar\n",
+      "\e[1G/",
+      "\e[1G/",
+    ].join)
+  end
+
+  it "logs a message ending with a newline above a spinner" do
+    spinner = TTY::Spinner.new(output: output)
+
+    2.times {
+      spinner.log "foo\n"
+      spinner.spin
+    }
+    output.rewind
+
+    expect(output.read).to eq([
+      "\e[2K\e[1Gfoo\n",
+      "\e[1G|",
+      "\e[1G|",
+      "\e[2K\e[1Gfoo\n",
+      "\e[1G/",
+      "\e[1G/",
+    ].join)
+  end
+
+  it "logs message under a spinner when done" do
+    spinner = TTY::Spinner.new(output: output)
+    2.times { spinner.spin }
+    spinner.stop
+
+    spinner.log "foo\nbar"
+
+    output.rewind
+    expect(output.read).to eq([
+      "\e[1G|",
+      "\e[1G/",
+      "\e[0m\e[2K\e[1G/\n",
+      "\e[2K\e[1Gfoo\n",
+      "\e[2K\e[1Gbar\n"
+    ].join)
+  end
+end