zle-bind-x

yank-git-branch.sh

#!/usr/bin/env zsh
# zsh uses its own line editor instead of readline: zle.
# 
# keys are bound to zle widgets
#
# Plan: create a widget, bind it to a key

# our custom zle widget for selecting a git branch using fzf
yank_git_branch() {
  local branch=$(git branch | awk '{print $NF}' | fzf)
  # zle uses a gap buffer, LBUFFER is what's left of the cursor 
  # and RBUFFER is what's right of the cursor
  #
  # Modifying either of the two keeps the cursor position in the right place (as opposed to modifying BUFFER).
  RBUFFER="${branch}$RBUFFER"
}

# register the widget with zle
zle -N yank-git-branch yank_git_branch

# now we can bind it!
bindkey -v '\C-j' yank-git-branch # use -e if you aren't using Vi keys in zsh