TSSERVER(1) General Commands Manual TSSERVER(1)
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tsserver - TypeScript standalone server
The TypeScript standalone server (aka tsserver) is a node executable
that encapsulates the TypeScript compiler and language services, and ex-
poses them through a JSON protocol. tsserver is well suited for editors
and IDE support.
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TSSERVER(1) General Commands Manual TSSERVER(1)
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Protocol
Definition
The server communication protocol is defined in the ts.server.protocol
namespace, declared in ]8;;https://github.com/microsoft/TypeScript/blob/main/lib/tsserverlibrary.d.ts\`tsserverlibrary.d.ts`]8;;\.
The executable can be found in lib folder under the typescript package.
npm install --save typescript
ls node_modules\typescript\lib\tsserver.js
Message format
tsserver listens on stdin and writes messages back to stdout.
Requests are JSON following the protocol definition. Here is an example
request to open a file c:/DefinitelyTyped/gregorian-calendar/index.d.ts:
{"seq":1,"type":"request","command":"open","arguments":{"file":"c:/DefinitelyTyped/gregorian-calendar/index.d.ts"}}
Responses are augmented JSON format. The Message starts with a header
with the content length followed by a line separator (\r\n) followed by
the response body as a JSON string:
Here is an example of a response for a quickinfo command:
Content-Length: 116
{"seq":0,"type":"response","command":"quickinfo","request_seq":2,"success":false,"message":"No content available."}
Similarly events have the same format as a response.
Here is an example event for error message:
Content-Length: 261
{"seq":0,"type":"event","event":"semanticDiag","body":{"file":"c:/DefinitelyTyped/gregorian-calendar/index.d.ts","diagnostics":[{"start":{"line":264,"offset":44},"end":{"line":264,"offset":50},"text":"Binding element 'Object'
implicitly has an 'any' type."}]}}
Commands
tsserver supports a set of commands. The full list of commands supported
by the server can be found under ]8;;https://github.com/microsoft/TypeScript/blob/main/src/server/protocol.ts\ts.server.protocol.CommandTypes]8;;\.
Each command is associated with a request and a response interface. For
instance command "completions" corresponds to request interface Comple-
tionsRequest, and response interface defined in CompletionsResponse.
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Sample implementations
Sublime text plugin
]8;;https://github.com/Microsoft/TypeScript-Sublime-Plugin\TypeScript-Sublime-Plugin]8;;\ is a Sublime text plugin written in Python
that uses tsserver.
Visual Studio Code
]8;;https://code.visualstudio.com/\VS Code]8;;\' s ]8;;https://github.com/microsoft/vscode/tree/master/extensions/typescript-language-features\TypeScript support]8;;\ is implemented in TypeScript using
tsserver.
Tide
]8;;https://github.com/ananthakumaran/tide\Tide]8;;\ is an elisp implementation for emacs plugin using tsserver
Neovim
]8;;https://github.com/mhartington/nvim-typescript\nvim-typescript]8;;\ is a neovim plugin using tsserver
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TSSERVER(1) General Commands Manual TSSERVER(1)
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Advanced topics
Logging
tsserver logging is configured through the TSS_LOG environment variable.
TSS_LOG can have the following format:
[-level <terse | normal | requestTime | verbose>]
[-traceToConsole <true | false>]
[-logToFile <true | false>]
[-file <log file path>]
Note: file defaults to __dirname\.log<PID> if not specified
Example: set TSS_LOG=-level verbose -file c:\tmp\tsserver.log
Cancellation
tsserver on startup will try to load module ./cancellationToken from the
containing directory. This module should export a factory function that
accepts a list of command line arguments and returns ]8;;https://github.com/Microsoft/TypeScript/blob/master/src/services/types.ts#L119-L121\HostCancellationTo-
ken]8;;\. tsserver will use this token to check if in-flight operation
should be cancelled.
NOTE: This token will be used for all operations so if one operation is
cancelled and cancellation was reported through the token then when an-
other operation is started - token should be reset into the non-can-
celled state.
Default implementation of the cancellation token uses the presence of
named pipes as a way to signal cancellation.
• Before spawning the server, the client generates a unique name. This
name is passed to the server as a cancellationPipeName command line
argument.
• If some operation on the client side should be cancelled - client
opens a named pipe with a name generated on step 1. Nothing needs to
be written in the pipe - default cancellation token will interpret
the presence of named pipe as a cancellation request.
• After receiving acknowledgment from the server, the client closes the
pipe so it can use the same pipe name for the next operation.
Server can split execution of some commands (like geterr) in a few steps
that will be executed with a delay. This allows it to react on user ac-
tions more promptly and not run heavy computations if their results will
not be used. However, it introduces a tricky moment in support of can-
cellations. By allowing request to be suspended and resumed later we
break the invariant that was the cornerstone for default implementation
of cancellation. Namely now requests can overlap so one pipe name can no
longer be used because client have no reason what request is currently
executing and will be cancelled. To deal with this issue tsserver allows
pipe name to be computed dynamically based on current request id. To en-
able this the client need to provide a value that ends with * as the
--cancellationPipeName argument. If provided cancellation pipe name ends
with * then default implementation of cancellation token will build ex-
pected pipe name as <cancellationPipeName argument without *><currentRe-
questId>. This will allow client to signal any request it thinks is in
flight by creating a named pipe with a proper name. Note that server
will always send requestCompleted message to denote that asynchronous
request was completed (either by running to completion or via cancella-
tion) so the client can close named pipe once this message is received.
Commandline options
--cancellationPipeName
Name of the pipe used as a request cancellation semaphore. See Cancellation for more information.
--syntaxOnly
A streamlined mode for when the server will only be answering syntactic queries.
--suppressDiagnosticEvents
Opt out of receiving events when new diagnostics are discovered (i.e. must request them explicitly).
--eventPort
Port used for receiving events. If non is specified events are sent to stdout.
--useSingleInferredProject
Put all open .ts and .js files that do not have a .tsconfig file in a common project
--noGetErrOnBackgroundUpdate
Opt out of starting getErr on projectsUpdatedInBackground event
--locale
The locale to use to show error messages, e.g. en-us.
Possible values are: English (US): en, Czech: cs, German: de, Spanish: es, French: fr, Italian: it, Japanese: ja, Korean: ko, Polish: pl,
Portuguese(Brazil): pt-BR, Russian: ru, Turkish: tr, Simplified Chinese: zh-CN, Traditional Chinese: zh-TW
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TSSERVER(1) General Commands Manual TSSERVER(1)
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Project System
There are three kinds of projects:
Configured Project
Configured projects are defined by a configuration file, which can be
Thateconfigurationofilelmarksathecprojectsrootilpath and defines what
Theesconfiguration file also provide the compiler options to be used for
this project.
]8;;http://www.typescriptlang.org/docs/handbook/tsconfig-json.html\tsconfig.jsonmdocumentation]8;;\.n in the
External Project
An external project represents host-specific project formats that TS is
The ahost is.responsible for supplying the list of files in this project
and compiler options to use.
Currently VS is the only consumer of this type of project, to model the
TS/JS files in a .csproj project.
Inferred Project
Iffearefileojdoes not have asconfigurationefile (tsconfig.jsonforejscon-
fig.json) in the current directory or any parent directories, the server
will create an inferred project for it.
The server will include the loose file, then includes all other files
included by triple slash references and module imports from the original
file transitively.
Thephosticanosetothewdefaultstof anfinferrediproject.inferred projects.
Relationship Among These Projects
In general, the relationship can be summarized as configured projects >
external projects > inferred projects.
For example, if file1.ts belongs to an inferred project, but later a new
Thennafterstheatsconfig.jsontfilefisefound, file1.ts will no longer be-
long to the previous inferred project but the newly created configured
Ifofile1.tstused to be the root file of the inferred project, that in-
ferred project will now be destroyed; otherwise it will remain with one
fewer file.
For another example, if a tsconfig.json file is created to include some
files used to belong to an external project (let's call it EP1), then in
the current implementation EP1 will be destroyed, all its files either
go to the new configured project or will belong to a new inferred
project the next time it is opened.
One thing to notice is that one file can belong to multiple projects of
the same kind at the same time. E.g., a file can be included by multiple
configured projects / inferred projects / external projects.
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