2 files changed, 48 insertions, 0 deletions
diff --git a/runtime/lua/vim/shared.lua b/runtime/lua/vim/shared.lua
index 631dd04c35..b5b04d7757 100644
--- a/runtime/lua/vim/shared.lua
+++ b/runtime/lua/vim/shared.lua
@@ -320,6 +320,26 @@ function vim.pesc(s)
   return s:gsub('[%(%)%.%%%+%-%*%?%[%]%^%$]', '%%%1')
 end
 
+--- Test if `prefix` is a prefix of `s` for strings.
+--
+-- @param s String to check
+-- @param prefix Potential prefix
+-- @return boolean True if prefix is a prefix of s
+function vim.startswith(s, prefix)
+  vim.validate { s = {s, 's'}; prefix = {prefix, 's'}; }
+  return s:sub(1, #prefix) == prefix
+end
+
+--- Test if `suffix` is a suffix of `s` for strings.
+--
+-- @param s String to check
+-- @param suffix Potential suffix
+-- @return boolean True if suffix is a suffix of s
+function vim.endswith(s, suffix)
+  vim.validate { s = {s, 's'}; suffix = {suffix, 's'}; }
+  return #suffix == 0 or s:sub(-#suffix) == suffix
+end
+
 --- Validates a parameter specification (types and values).
 ---
 --- Usage example:
diff --git a/test/functional/lua/vim_spec.lua b/test/functional/lua/vim_spec.lua
index 45818d2a99..22c975147f 100644
--- a/test/functional/lua/vim_spec.lua
+++ b/test/functional/lua/vim_spec.lua
@@ -117,6 +117,34 @@ describe('lua stdlib', function()
     eq(1, funcs.luaeval('vim.stricmp("\\0C\\0", "\\0B\\0")'))
   end)
 
+  it('vim.startswith', function()
+    eq(true, funcs.luaeval('vim.startswith("123", "1")'))
+    eq(true, funcs.luaeval('vim.startswith("123", "")'))
+    eq(true, funcs.luaeval('vim.startswith("123", "123")'))
+    eq(true, funcs.luaeval('vim.startswith("", "")'))
+
+    eq(false, funcs.luaeval('vim.startswith("123", " ")'))
+    eq(false, funcs.luaeval('vim.startswith("123", "2")'))
+    eq(false, funcs.luaeval('vim.startswith("123", "1234")'))
+
+    eq("string", type(pcall_err(funcs.luaeval, 'vim.startswith("123", nil)')))
+    eq("string", type(pcall_err(funcs.luaeval, 'vim.startswith(nil, "123")')))
+  end)
+
+  it('vim.endswith', function()
+    eq(true, funcs.luaeval('vim.endswith("123", "3")'))
+    eq(true, funcs.luaeval('vim.endswith("123", "")'))
+    eq(true, funcs.luaeval('vim.endswith("123", "123")'))
+    eq(true, funcs.luaeval('vim.endswith("", "")'))
+
+    eq(false, funcs.luaeval('vim.endswith("123", " ")'))
+    eq(false, funcs.luaeval('vim.endswith("123", "2")'))
+    eq(false, funcs.luaeval('vim.endswith("123", "1234")'))
+
+    eq("string", type(pcall_err(funcs.luaeval, 'vim.endswith("123", nil)')))
+    eq("string", type(pcall_err(funcs.luaeval, 'vim.endswith(nil, "123")')))
+  end)
+
   it("vim.str_utfindex/str_byteindex", function()
     exec_lua([[_G.test_text = "xy åäö ɧ 汉语 ↥ 🤦x🦄 å بِيَّ"]])
     local indicies32 = {[0]=0,1,2,3,5,7,9,10,12,13,16,19,20,23,24,28,29,33,34,35,37,38,40,42,44,46,48}