1 files changed, 179 insertions, 0 deletions
diff --git a/lua/telescope/debounce.lua b/lua/telescope/debounce.lua
new file mode 100644
index 0000000..329cdc5
--- /dev/null
+++ b/lua/telescope/debounce.lua
@@ -0,0 +1,179 @@
+-- Credit: https://gist.github.com/runiq/31aa5c4bf00f8e0843cd267880117201
+--
+
+local M = {}
+
+---Validates args for `throttle()` and  `debounce()`.
+local function td_validate(fn, ms)
+  vim.validate{
+    fn = { fn, 'f' },
+    ms = {
+      ms,
+      function(ms)
+        return type(ms) == 'number' and ms > 0
+      end,
+      "number > 0",
+    },
+  }
+end
+
+--- Throttles a function on the leading edge. Automatically `schedule_wrap()`s.
+---
+--@param fn (function) Function to throttle
+--@param timeout (number) Timeout in ms
+--@returns (function, timer) throttled function and timer. Remember to call
+---`timer:close()` at the end or you will leak memory!
+function M.throttle_leading(fn, ms)
+  td_validate(fn, ms)
+  local timer = vim.loop.new_timer()
+  local running = false
+
+  local function wrapped_fn(...)
+    if not running then
+      timer:start(ms, 0, function()
+        running = false
+      end)
+      running = true
+      pcall(vim.schedule_wrap(fn), select(1, ...))
+    end
+  end
+  return wrapped_fn, timer
+end
+
+--- Throttles a function on the trailing edge. Automatically
+--- `schedule_wrap()`s.
+---
+--@param fn (function) Function to throttle
+--@param timeout (number) Timeout in ms
+--@param last (boolean, optional) Whether to use the arguments of the last
+---call to `fn` within the timeframe. Default: Use arguments of the first call.
+--@returns (function, timer) Throttled function and timer. Remember to call
+---`timer:close()` at the end or you will leak memory!
+function M.throttle_trailing(fn, ms, last)
+  td_validate(fn, ms)
+  local timer = vim.loop.new_timer()
+  local running = false
+
+  local wrapped_fn
+  if not last then
+    function wrapped_fn(...)
+      if not running then
+        local argv = {...}
+        local argc = select('#', ...)
+
+        timer:start(ms, 0, function()
+          running = false
+          pcall(vim.schedule_wrap(fn), unpack(argv, 1, argc))
+        end)
+        running = true
+      end
+    end
+  else
+    local argv, argc
+    function wrapped_fn(...)
+      argv = {...}
+      argc = select('#', ...)
+
+      if not running then
+        timer:start(ms, 0, function()
+          running = false
+          pcall(vim.schedule_wrap(fn), unpack(argv, 1, argc))
+        end)
+        running = true
+      end
+    end
+  end
+  return wrapped_fn, timer
+end
+
+--- Debounces a function on the leading edge. Automatically `schedule_wrap()`s.
+---
+--@param fn (function) Function to debounce
+--@param timeout (number) Timeout in ms
+--@returns (function, timer) Debounced function and timer. Remember to call
+---`timer:close()` at the end or you will leak memory!
+function M.debounce_leading(fn, ms)
+  td_validate(fn, ms)
+  local timer = vim.loop.new_timer()
+  local running = false
+
+  local function wrapped_fn(...)
+    timer:start(ms, 0, function()
+      running = false
+    end)
+
+    if not running then
+      running = true
+      pcall(vim.schedule_wrap(fn), select(1, ...))
+    end
+  end
+  return wrapped_fn, timer
+end
+
+--- Debounces a function on the trailing edge. Automatically
+--- `schedule_wrap()`s.
+---
+--@param fn (function) Function to debounce
+--@param timeout (number) Timeout in ms
+--@param first (boolean, optional) Whether to use the arguments of the first
+---call to `fn` within the timeframe. Default: Use arguments of the last call.
+--@returns (function, timer) Debounced function and timer. Remember to call
+---`timer:close()` at the end or you will leak memory!
+function M.debounce_trailing(fn, ms, first)
+  td_validate(fn, ms)
+  local timer = vim.loop.new_timer()
+  local wrapped_fn
+
+  if not first then
+    function wrapped_fn(...)
+      local argv = {...}
+      local argc = select('#', ...)
+
+      timer:start(ms, 0, function()
+        pcall(vim.schedule_wrap(fn), unpack(argv, 1, argc))
+      end)
+    end
+  else
+    local argv, argc
+    function wrapped_fn(...)
+      argv = argv or {...}
+      argc = argc or select('#', ...)
+
+      timer:start(ms, 0, function()
+        pcall(vim.schedule_wrap(fn), unpack(argv, 1, argc))
+      end)
+    end
+  end
+  return wrapped_fn, timer
+end
+
+--- Test deferment methods (`{throttle,debounce}_{leading,trailing}()`).
+---
+--@param bouncer (string) Bouncer function to test
+--@param ms (number, optional) Timeout in ms, default 2000.
+--@param firstlast (bool, optional) Whether to use the 'other' fn call
+---strategy.
+function M.test_defer(bouncer, ms, firstlast)
+  local bouncers = {
+    tl = M.throttle_leading,
+    tt = M.throttle_trailing,
+    dl = M.debounce_leading,
+    dt = M.debounce_trailing,
+  }
+
+  local timeout = ms or 2000
+
+  local bounced = bouncers[bouncer](
+  function(i) vim.cmd('echom "' .. bouncer .. ': ' .. i .. '"') end,
+  timeout,
+  firstlast
+  )
+
+  for i, _ in ipairs{1,2,3,4,5} do
+    bounced(i)
+    vim.schedule(function () vim.cmd('echom ' .. i) end)
+    vim.fn.call("wait", {1000, "v:false"})
+  end
+end
+
+return M