POSIX shell scripts and Helix config to auto-select when to use Deno, TS LS, and/or Prettier for the current file. Bonus script to auto-update Helix grammars.

deno_lsp_or_tsls

#!/bin/sh
#
# Runs `deno lsp` if a Deno configuration file is found, otherwise runs
# `typescript-language-server`
#
# Usage: deno_lsp_or_tsls ...[arguments]
#
# This script is intended to be run by the Helix editor, or any other editor
# that includes the current buffer's filename as the final field in its process
# command line.
#
set -e

PATH="$(dirname "$(realpath "${0}")"):${PATH}"

file=$(
  ps -p "${PPID}" -o "command=" \
    | awk '{ print $NF }'
)
prev=""
dir=$(dirname "$(realpath "${file}")")
cd "${dir}"

file=$(basename "${file}")

should_deno_lsp() (
  case "${dir}" in
    "${prev}") return 1 ;;
    *)
      if test -r "deno.json" \
        -o -r "deno.jsonc"; then
        return 0
      elif test -r "package.json"; then
        return 1
      else
        cd ..
        prev="${dir}"
        dir=$(pwd)
        should_deno_lsp
      fi
      ;;
  esac
)
if should_deno_lsp; then
  if qtype deno; then
    exec deno lsp --unstable "${@}"
  fi
elif qtype typescript-language-server; then
  exec typescript-language-server --stdio "${@}"
fi

exit 1

hx_grammars

#!/bin/sh
#
# Updates Helix grammars defined in `${XDG_CONFIG_HOME}/helix/languages.toml` if
# any new revisions are found
#
# Usage: hx_grammars
#
# All grammars are compiled, but only those specified in `languages.toml` are
# retained.
#
set -e

PATH="$(dirname "$(realpath "${0}")"):${PATH}"

qtype git hx jq toml

helix_dir="${XDG_CONFIG_HOME}/helix"
grammars_dir="${helix_dir}/runtime/grammars"
languages="${helix_dir}/languages.toml"

# Get latest git revisions for grammars defined in `${languages}`
#
grammar_names=""
do_update="False"
grammars=$(
  toml get "${languages}" grammar \
    | jq '.[] | "name=\"\(.name)\";repo=\"\(.source.git)\";current_revision=\"\(.source.rev)\""' --raw-output
)
cd "/tmp/"
for grammar in ${grammars}; do
  name="None"
  repo="None"
  current_revision="None"
  eval "${grammar}"
  case "${name}${repo}${current_revision}" in
    *None*) continue ;;
  esac
  grammar_names=$(
    case "${grammar_names}" in
      "") echo "${name}" ;;
      *) echo "${grammar_names}" "${name}" ;;
    esac
  )
  repo_dir=$(basename "${repo}")
  echo "Searching for ${name} grammar updates..."
  git clone --depth=1 --quiet "${repo}.git"
  cd "${repo_dir}"
  new_revision=$(git rev-parse HEAD)
  cd "/tmp/"
  rm -rf "${repo_dir}"
  case "${new_revision}" in
    "${current_revision}") continue ;;
    *)
      do_update="True"
      sed -i "s/${current_revision}/${new_revision}/" "${languages}"
      ;;
  esac
done

# Update compiled grammars if needed
#
case "${do_update}" in
  True) echo "Compiling new grammars..." ;;
  False)
    echo "No new grammars found"
    exit 0
    ;;
esac
for action in fetch build; do
  hx --grammar "${action}" >/dev/null
done
rm -rf "${grammars_dir}/sources/"
for grammar in ${grammar_names}; do
  cp "${grammars_dir}/${grammar}.so" "/tmp/"
done
rm -rf "${grammars_dir}"
mkdir -p "${grammars_dir}"
for grammar in ${grammar_names}; do
  mv "/tmp/${grammar}.so" "${grammars_dir}/"
done
echo "Grammars updated"

exit 0

languages.toml

[[language]]
name = "bash"
auto-format = true

[language.formatter]
command = "shfmt"
args = [
  "--binary-next-line",
  "--case-indent",
  "--indent=2",
  "--simplify",
]

[[language]]
name = "elixir"
auto-format = true

[[grammar]]
name = "elixir"

[grammar.source]
git = "https://github.com/elixir-lang/tree-sitter-elixir"
rev = "a2861e88a730287a60c11ea9299c033c7d076e30"

[[language]]
name = "erlang"
auto-format = true

[[grammar]]
name = "erlang"

[grammar.source]
git = "https://github.com/the-mikedavis/tree-sitter-erlang"
rev = "bf56054c7c1bc66a27552b19702ffac8189ac7ec"

[[language]]
name = "gleam"
auto-format = true
formatter = { command = "gleam", args = ["format", "--stdin"] }

[[grammar]]
name = "gleam"

[grammar.source]
git = "https://github.com/gleam-lang/tree-sitter-gleam"
rev = "399172f660160258ede7d8e1d769f7fc5f61ff33"

[[language]]
name = "javascript"
auto-format = true
formatter = { command = "prettier_or_deno_fmt" }
language-servers = ["deno-lsp-or-tsls"]

[[language]]
name = "json"
auto-format = true
formatter = { command = "prettier_or_deno_fmt" }

[[language]]
name = "markdown"
auto-format = true
formatter = { command = "prettier_or_deno_fmt" }

[[language]]
name = "php"
indent = { tab-width = 2, unit = "\t" }

[[language]]
name = "sql"
auto-format = true
formatter = { command = "prettier", args = ["--stdin-filepath=query.sql", "--config-precedence=file-override", "--sql-keyword-case=lower"] }

[[language]]
name = "typescript"
auto-format = true
formatter = { command = "prettier_or_deno_fmt" }
language-servers = ["deno-lsp-or-tsls"]

[language-server.deno-lsp-or-tsls]
command = "deno_lsp_or_tsls"
environment = { NO_COLOR = "1" }
config.hostInfo = "helix"

[language-server.deno-lsp-or-tsls.config.deno]
enable = true
unstable = true
cacheOnSave = true
suggest = { completeFunctionCalls = false, imports = { hosts = { "https://deno.land" = true } } }
# suggest = { completeFunctionCalls = false, imports = { hosts = { "https://deno.land" = true, "https://crux.land" = true, "https://x.nest.land" = true } } }
inlayHints.parameterNames.enabled = "all"
inlayHints.parameterTypes.enabled = true
inlayHints.variableTypes.enabled = true
inlayHints.propertyDeclarationTypes.enabled  = true
inlayHints.functionLikeReturnTypes.enabled = true
inlayHints.enumMemberValues.enabled = true

[language-server.deno-lsp-or-tsls.config.typescript.inlayHints]
includeInlayEnumMemberValueHints = true
includeInlayFunctionLikeReturnTypeHints = true
includeInlayFunctionParameterTypeHints = true
includeInlayParameterNameHints = "all"
includeInlayParameterNameHintsWhenArgumentMatchesName = true
includeInlayPropertyDeclarationTypeHints = true
includeInlayVariableTypeHints = true

[language-server.deno-lsp-or-tsls.config.javascript.inlayHints]
includeInlayEnumMemberValueHints = true
includeInlayFunctionLikeReturnTypeHints = true
includeInlayFunctionParameterTypeHints = true
includeInlayParameterNameHints = "all"
includeInlayParameterNameHintsWhenArgumentMatchesName = true
includeInlayPropertyDeclarationTypeHints = true
includeInlayVariableTypeHints = true

prettier_or_deno_fmt

#!/bin/sh
#
# Formats stdin using Prettier if a configuration file is found, otherwise uses
# the Deno formatter
#
# Usage: prettier_or_deno_fmt
#
# This script is intended to be run by the Helix editor, or any other editor
# that includes the current buffer's filename as the final field in its process
# command line.
#
set -e

PATH="$(dirname "$(realpath "${0}")"):${PATH}"

file=$(
  ps -p "${PPID}" -o "command=" \
    | awk '{ print $NF }'
)
prev=""
dir=$(dirname "$(realpath "${file}")")
cd "${dir}"

file=$(basename "${file}")

should_prettier() (
  case "${dir}" in
    "${prev}") return 1 ;;
    *)
      if grep -iqs "prettier" "package.json" \
        || test -r ".prettierrc" \
          -o -r ".prettierrc.json" \
          -o -r ".prettierrc.yml" \
          -o -r ".prettierrc.yaml" \
          -o -r ".prettierrc.json5" \
          -o -r ".prettierrc.js" \
          -o -r ".prettierrc.cjs" \
          -o -r "prettier.config.js" \
          -o -r "prettier.config.cjs" \
          -o -r ".prettierrc.toml"; then
        return 0
      elif test -r "deno.json" \
        -o -r "deno.jsonc"; then
        return 1
      else
        cd ..
        prev="${dir}"
        dir=$(pwd)
        should_prettier
      fi
      ;;
  esac
)
if should_prettier; then
  if qtype prettier; then
    exec prettier \
      --loglevel=silent \
      --stdin-filepath="${file}"
  fi
elif qtype deno; then
  case "${file}" in
    .*.*) ext="${file##*.}" ;;
    .*) ext="" ;;
    *.*) ext="${file##*.}" ;;
    *) ext="" ;;
  esac
  exec deno fmt \
    --ext="${ext}" \
    --quiet \
    --unstable \
    -
fi

exit 1