refactor(angularls): better root path resolution

Problem:
The current config for Angular LS make strong assumptions when trying to
find the root dir, which can lead to unexpected LSP crashes.

Solution:
By defining the 'cmd' field as a function, the config employs Neovim's
LSP root resolution to identify the correct path and find the relevant
node_modules folder.

Author: Erikson Kaszubowski

lsp/angularls.lua

@@ -14,72 +14,84 @@
 
 -- Angular requires a node_modules directory to probe for @angular/language-service and typescript
 -- in order to use your projects configured versions.
-local root_dir = vim.fn.getcwd()
-local node_modules_dir = vim.fs.find('node_modules', { path = root_dir, upward = true })[1]
-local project_root = node_modules_dir and vim.fs.dirname(node_modules_dir) or '?'
+local fs, fn, uv = vim.fs, vim.fn, vim.uv
 
-local function get_probe_dir()
-  return project_root and (project_root .. '/node_modules') or ''
-end
+local function collect_node_modules(root_dir)
+  local results = {}
 
-local function get_angular_core_version()
-  if not project_root then
-    return ''
+  local project_node = fs.joinpath(root_dir, 'node_modules')
+  if uv.fs_stat(project_node) then
+    table.insert(results, project_node)
   end
 
-  local package_json = project_root .. '/package.json'
-  if not vim.uv.fs_stat(package_json) then
-    return ''
+  local ngserver_exe = fn.exepath('ngserver')
+  if ngserver_exe and #ngserver_exe > 0 then
+    local realpath = uv.fs_realpath(ngserver_exe) or ngserver_exe
+    local candidate = fs.normalize(fs.joinpath(fs.dirname(realpath), '../../node_modules'))
+    if uv.fs_stat(candidate) then
+      table.insert(results, candidate)
+    end
   end
 
-  local contents = io.open(package_json):read '*a'
-  local json = vim.json.decode(contents)
-  if not json.dependencies then
-    return ''
+  local internal_servers = fn.globpath(fn.stdpath('data'), '**/node_modules/.bin/ngserver', true, true)
+  for _, exe in ipairs(internal_servers) do
+    local realpath = uv.fs_realpath(exe) or exe
+    local candidate = fs.normalize(fs.joinpath(fs.dirname(realpath), '../../node_modules'))
+    if uv.fs_stat(candidate) then
+      table.insert(results, candidate)
+    end
   end
 
-  local angular_core_version = json.dependencies['@angular/core']
-
-  angular_core_version = angular_core_version and angular_core_version:match('%d+%.%d+%.%d+')
-
-  return angular_core_version
+  return results
 end
 
-local default_probe_dir = get_probe_dir()
-local default_angular_core_version = get_angular_core_version()
+local function get_angular_core_version(root_dir)
+  local package_json = fs.joinpath(root_dir, 'package.json')
+  if not uv.fs_stat(package_json) then
+    return ''
+  end
+
+  local ok, f = pcall(io.open, package_json, 'r')
+  if not ok or not f then
+    return ''
+  end
 
--- structure should be like
--- - $EXTENSION_PATH
---   - @angular
---     - language-server
---       - bin
---         - ngserver
---   - typescript
-local ngserver_exe = vim.fn.exepath('ngserver')
-local ngserver_path = #(ngserver_exe or '') > 0 and vim.fs.dirname(vim.uv.fs_realpath(ngserver_exe)) or '?'
-local extension_path = vim.fs.normalize(vim.fs.joinpath(ngserver_path, '../../../'))
+  local json = vim.json.decode(f:read('*a')) or {}
+  f:close()
 
--- angularls will get module by `require.resolve(PROBE_PATH, MODULE_NAME)` of nodejs
-local ts_probe_dirs = vim.iter({ extension_path, default_probe_dir }):join(',')
-local ng_probe_dirs = vim
-  .iter({ extension_path, default_probe_dir })
-  :map(function(p)
-    return vim.fs.joinpath(p, '/@angular/language-server/node_modules')
-  end)
-  :join(',')
+  local version = (json.dependencies or {})['@angular/core'] or ''
+  return version:match('%d+%.%d+%.%d+') or ''
+end
 
 ---@type vim.lsp.Config
 return {
-  cmd = {
-    'ngserver',
-    '--stdio',
-    '--tsProbeLocations',
-    ts_probe_dirs,
-    '--ngProbeLocations',
-    ng_probe_dirs,
-    '--angularCoreVersion',
-    default_angular_core_version,
-  },
+  cmd = function(dispatchers, config)
+    local root_dir = config.root or fn.getcwd()
+    local node_paths = collect_node_modules(root_dir)
+
+    local ts_probe = table.concat(node_paths, ',')
+    local ng_probe = table.concat(
+      vim
+        .iter(node_paths)
+        :map(function(p)
+          return fs.joinpath(p, '@angular/language-server/node_modules')
+        end)
+        :totable(),
+      ','
+    )
+    local cmd = {
+      'ngserver',
+      '--stdio',
+      '--tsProbeLocations',
+      ts_probe,
+      '--ngProbeLocations',
+      ng_probe,
+      '--angularCoreVersion',
+      get_angular_core_version(root_dir),
+    }
+    return vim.lsp.rpc.start(cmd, dispatchers)
+  end,
+
   filetypes = { 'typescript', 'html', 'typescriptreact', 'typescript.tsx', 'htmlangular' },
-  root_markers = { 'angular.json', 'nx.json' },
+  root_markers = { 'angular.json', 'nx.json', 'package.json' },
 }