Enhancement: allow for up/down swapping from beginning of indented lines

At the time of writing, it seems possible (although not certain)
that #22 is from the lack of this feature.

Now up/down swaps will work if you're on a line that can be up/down
swapped, even if your cursor is at a column number less than where the
code on the line starts.

Author: aaronik

lua/treewalker/swap.lua

@@ -47,6 +47,7 @@ local function get_highest_string_node_pipe(node)
 end
 
 function M.swap_down()
+  vim.cmd("normal! ^")
   if not is_on_target_node() then return end
   if not is_supported_ft() then return end
 
@@ -78,6 +79,7 @@ function M.swap_down()
 end
 
 function M.swap_up()
+  vim.cmd("normal! ^")
   if not is_on_target_node() then return end
   if not is_supported_ft() then return end
 

tests/fixtures/typescript.ts

@@ -98,3 +98,15 @@ function sleep(ms: number): Promise<void> {
   return new Promise((resolve) => setTimeout(resolve, ms));
 }
 
+// Courtesy of pkenway-figma in #22
+const x = 1
+const y = 2
+
+function doThings(b: number ) {
+  const i = 1
+  const j = 2
+
+  for (let a = i;a < j;a++) {
+    console.log(a)
+  }
+}

tests/treewalker/swap_spec.lua

@@ -464,3 +464,25 @@ describe("Swapping in a python file:", function()
     helpers.assert_cursor_at(135, 1, "|def other")
   end)
 end)
+
+describe("Swapping in a typescript file:", function()
+  before_each(function()
+    load_fixture("/typescript.ts")
+  end)
+
+  it("swaps up annotated functions of different length", function()
+    vim.fn.cursor(106, 1) -- |  const i = 1
+    tw.swap_down()
+    helpers.assert_cursor_at(107, 3)
+    assert.same('  const j = 2', lines.get_line(106))
+    assert.same('  const i = 1', lines.get_line(107))
+  end)
+
+  it("swaps down annotated functions of different length", function()
+    vim.fn.cursor(107, 1) -- |  const i = 1
+    tw.swap_up()
+    helpers.assert_cursor_at(106, 3)
+    assert.same('  const j = 2', lines.get_line(106))
+    assert.same('  const i = 1', lines.get_line(107))
+  end)
+end)