+ # else merge with prev/outer text run
+ pcb = @find_block_parent prev_cursor.n
+ while block.children.length > 0
+ @move_node block.children[0], pcb
+ @remove_node block
+ # merge possible consecutive text nodes at @cursor
+ merge_state = n: @cursor.n
+ @_merge_left merge_state
+ @text_cleanup merge_state.n
+ new_cursor = new_cursor_position n: merge_state.n, i: merge_state.i
+ else # at start of text node, but not start of text run
+ prev = run[run_i - 1]
+ if prev.type is 'text' # if previous in text run is text
+ if prev.text.length is 1 # if emptying prev (in text run)
+ @_backspace_node_helper prev, run, run_i
+ merge_state = n: @cursor.n, i: @cursor.i
+ @_merge_left merge_state
+ @text_cleanup merge_state.n
+ new_cursor = new_cursor_position n: merge_state.n, i: merge_state.i
+ else # prev in run is text with muliple chars
+ # delete last character in prev
+ prev.text = prev.text.substr(0, prev.text.length - 1)
+ prev.el.textContent = prev.text
+ @text_cleanup @cursor.n
+ new_cursor = new_cursor_position n: @cursor.n, i: @cursor.i
+ else if prev.name is 'br' or prev.name is 'hr'
+ @_backspace_node_helper prev, run, run_i
+ merge_state = n: @cursor.n, i: @cursor.i
+ @_merge_left merge_state
+ @text_cleanup merge_state.n
+ new_cursor = new_cursor_position n: merge_state.n, i: merge_state.i
+ # FIXME implement this:
+ # else # if prev (in run) is inline-block
+ # if that inline-block has text in it
+ # delete last char in prev inlineblock
+ # if that empties it
+ # delete it
+ # merge left
+ # else
+ # move cursor inside
+ # else
+ # delete prev (inline) block
+ # merge left
+ # auto-delete this @cursor.parent(s) if this empties them
+ else # cursor is not at start of text node
+ run ?= @get_text_run @cursor.n
+ if @cursor.n.text.length is 1 # if emptying text node
+ if run.length is 1 # if emptying text run (of text/br/hr/inline-block)
+ # remove inline-parents of @cursor.n
+ block = @find_block_parent @cursor.n
+ changed = false
+ n = @cursor.n.parent
+ # note: this doesn't use _backspace_node_helper because:
+ # 1. we don't want to delete the target node (we're replacing it's contents)
+ # 2. we want to track whether anything was removed
+ # 3. we know already know there's no other text from this run anywhere
+ while n and n isnt block
+ changed = true
+ while n.children.length > 0
+ @move_node n.children[0], n.parent, n
+ @remove_node n
+ n = n.parent
+ # replace @cursor.n with a single (preserved) space
+ if @cursor.n.text != ' '
+ changed = true
+ @cursor.n.text = @cursor.n.el.textContent = ' '
+ if changed
+ @text_cleanup @cursor.n
+ # place the cursor to the left of that space
+ new_cursor = new_cursor_position n: @cursor.n, i: 0
+ else # emptying a text node (but not a whole text run)
+ # figure out where cursor should land
+ block = @find_block_parent @cursor.n
+ new_cursor = find_prev_cursor_position @tree, n: @cursor.n, i: 0
+ ncb = @find_block_parent new_cursor.n
+ if ncb isnt block
+ new_cursor = find_next_cursor_position @tree, n: @cursor.n, i: 1
+ # delete text node and cleanup emptied parents
+ run_i = run.indexOf @cursor.n
+ @_backspace_node_helper @cursor.n, run, run_i
+ # see if new adjacent siblings should merge
+ # TODO make smarter
+ if run_i > 0 and run_i + 1 < run.length
+ if run[run_i - 1].type is 'text' and run[run_i + 1].type is 'text'
+ merge_state = n: run[run_i + 1]
+ @_merge_left merge_state
+ if merge_state.moved_cursor
+ new_cursor = merge_state
+ # update whitespace preservation
+ @text_cleanup(block)
+ # update cursor x/y in case things moved around
+ if new_cursor?
+ if new_cursor.n.el.parentNode # still in dom after cleanup
+ new_cursor = new_cursor_position n: new_cursor.n, i: new_cursor.i
+ else
+ new_cursor = null
+ else # there's a char left of cursor that we can delete without emptying anything
+ # delete character
+ need_text_cleanup = true
+ if @cursor.i > 1 and @cursor.i < @cursor.n.text.length
+ pre = @cursor.n.text.substr(@cursor.i - 2, 3)
+ post = pre.charAt(0) + pre.charAt(2)
+ if str_has_ws_run(pre) is str_has_ws_run(post)
+ need_text_cleanup = false
+ @remove_character(@cursor.n, @cursor.i - 1)
+ # call text_cleanup if whe created/removed a whitespace run
+ if need_text_cleanup
+ @text_cleanup @cursor.n
+ new_cursor = new_cursor_position n: @cursor.n, i: @cursor.i - 1
+ # mark document changed and move the cursor
+ if changed?