# How to ask what the code means

This guide shows how to follow a name through a JavaScript project: what it is, where it is declared, and what is wrong with it. It assumes Turbo JS is installed and the language server is running — the status bar says `LSP: ready` when it is.

For moving around a file — searching, jumping to a line, switching windows — see [How to move around a file](navigate-code.md) instead.

## Put the cursor on a name

Any character of it will do. Every question below asks about the **position of the cursor**, not about a selection, so there is nothing to highlight first.

## Ask

| To find | Do | Shortcut |
| --- | --- | --- |
| What it is | **Code ▸ Describe symbol** | `F1` |
| Where it is declared | **Code ▸ Go to definition** | `F12` |
| Where its *type* is declared | **Code ▸ Go to type definition** | |
| What implements it | **Code ▸ Find implementations…** | |
| Everywhere it is used | **Code ▸ Find references…** | `Shift-F12` |

`typescript-language-server` answers all five for plain JavaScript. **Describe symbol** shows a declaration's signature and the JSDoc comment written immediately above it; **Go to type definition** on `const shape = new Circle()` goes to `class Circle`; **Find implementations…** on a class lists its subclasses; **Find references…** lists the declaration and every call.

One answer takes you straight there. Several open a list showing each file, its line, and the text of that line; move with the arrow keys, `Enter` to go, `Esc` to stay where you are.

## When nothing comes back

Three different things look alike, and the status bar tells them apart:

| It says | Meaning |
| --- | --- |
| `No … found`, in the question's own words | The server answered, and there are none |
| `LSP: starting…` | The server has not finished starting. Wait a moment and ask again. |
| `LSP: off` on the status bar | No server is running. See [How to enable completion](enable-completion.md). |
| `LSP: no typescript-language-server — npm install -g typescript-language-server typescript@6` | There is no `typescript-language-server` on `PATH`, nor in the directories nvm, npm, pnpm and Volta install into. See [How to enable completion](enable-completion.md). |

## Find something by name instead

- **Code ▸ Symbol in file…** lists what the file in front declares, indented, with each symbol's kind — the functions and the classes. An outline you can walk; choosing one goes to it.
- **Code ▸ Symbol in project…** (`Ctrl-T`) asks for a name and searches the whole project.

## See what is wrong

**Code ▸ Problems…** lists every problem the server has reported, for **every file it has loaded** — usually more than the one you are editing. Choosing one goes to the line.

`typescript-language-server` reports **syntax errors** in a plain `.js` file, on open and again on every edit: a `function main( {` gets a `×` in the gutter and a `⚠` message on the status bar. A type mistake gets no mark unless you ask for checking — put `// @ts-check` on the first line of the file, or `checkJs` in a `jsconfig.json` — and then type errors arrive the same way.

Lines with a problem carry a mark in the gutter, beside the line number:

| Mark | Meaning |
| --- | --- |
| `×` | An error |
| `!` | A warning |
| `i` | Information |
| `·` | A hint |

A line with more than one problem shows the worst of them.

**The marks need the line numbers.** They sit in the column that separates the numbers from the text, so hiding the gutter with **Options ▸ Line numbers** hides them too.

## See also

- Every item and its key: [Menus](../reference/menus.md)
- Getting a server running: [How to enable completion](enable-completion.md)
- What the editor asks, and why: [Colouring and completion](../explanation/colouring-and-completion.md)
- What `typescript-language-server` answers, exactly: [JavaScript tools](../reference/javascript-tools.md)