romainl's node.js require.resolve()

after/filetype/javascript.vim

@@ -0,0 +1,105 @@
+" https://gist.github.com/romainl/1f50c55b0ee92e5420de51e6c4b38491
+
+setlocal includeexpr=RESOLVE(v:fname)
+
+function! RESOLVE(module) abort
+    let built_ins = [
+    \ "assert",
+    \ "async_hooks",
+    \ "child_process",
+    \ "cluster",
+    \ "crypto",
+    \ "dns",
+    \ "domain",
+    \ "events",
+    \ "fs",
+    \ "http",
+    \ "http2",
+    \ "https",
+    \ "inspector",
+    \ "net",
+    \ "os",
+    \ "path",
+    \ "perf_hooks",
+    \ "punycode",
+    \ "querystring",
+    \ "readline",
+    \ "stream",
+    \ "string_decoder",
+    \ "tls",
+    \ "tty",
+    \ "dgram",
+    \ "url",
+    \ "util",
+    \ "v8",
+    \ "vm",
+    \ "zlib" ]
+
+    " There's no source file for built-in node modules.
+    " Example: var http = require('http');
+    if index(built_ins, a:module) != -1
+        return 0
+    endif
+
+    " Handling absolute and relative paths.
+    " Example: var foo = require('./foo.js');
+    if a:module =~ '^\/' || a:module =~ '^\.\{1,2}\/'
+        let root = fnamemodify(substitute(finddir("node_modules", ".;"), '/node_modules', '', ''), ':p:h:h')
+        if a:module =~ '^\.\{1,2}\/'
+            let module = substitute(a:module, '^\.\{1,2}\/', '', '')
+        endif
+
+        let filename = 0
+        try
+            let filename = findfile(module, root)
+        catch
+            try
+                let filename = findfile(module . ".js", root)
+            catch
+                try
+                    let filename = findfile(module . "/index.js", root)
+                catch
+                    let filename = 0
+                endtry
+            endtry
+        endtry
+
+        return filename
+    endif
+
+    " Handling vendored-in modules.
+    " Example: var _ = require('lodash');
+    for dir in NODE_MODULES_PATHS()
+        " require('module') => node_modules/module/package.json#main => node_modules/module/**/...
+        if filereadable(dir . "/" . a:module . "/package.json")
+            let package = json_decode(join(readfile(dir . "/" . a:module . "/package.json")))
+            return dir . "/" . a:module . "/" . substitute(get(package, "main", "index.js"), '^\.\{1,2}\/', '', '')
+        endif
+
+        " require('module') => node_modules/module/index.js
+        if filereadable(dir . "/" . a:module . "/index.js")
+            return dir . "/" . a:module . "/index.js"
+        endif
+
+        " require('module') => node_modules/module.js
+        if filereadable(dir . "/" . a:module . ".js")
+            return dir . "/" . a:module . ".js"
+        endif
+    endfor
+
+    " well, well, well
+    return 0
+endfunction
+
+function! NODE_MODULES_PATHS() abort
+    " node_modules/
+    let node_modules = finddir("node_modules", ".;")
+
+    " node_modules/foo/node_modules/
+    let basic_dirs = extend([node_modules], globpath(node_modules, "*/node_modules", 1, 1))
+
+    " node_modules/@foo/bar/node_modules/
+    let all_dirs = extend(basic_dirs, globpath(node_modules, "@*/*/node_modules", 1, 1))
+
+    return all_dirs
+endfunction