coc-settings.json

{
  // Require .prettierrc
  "prettier.requireConfig": true,

  // Tslint on save
  "tslint.enable": true,
  "tslint.autoFixOnSave": true,

  // Run prettier (and others)
  "coc.preferences.formatOnSaveFiletypes": [
    "css",
    "markdown",
    "Markdown",
    "javascript",
    "javascriptreact",
    "typescript",
    "typescriptreact"
  ]
}