ERROR prettier.resolveConfig.sync is not a function

Since the last update 0.39.0 I am getting the following error when trying to format a file:

Prettier debug output:

Atom version: 1.20.0
prettier-atom version: 0.39.0
prettier version: 1.7.0
prettier-eslint version: 8.1.0
prettier-atom configuration: {
  "formatOnSaveOptions": {
    "enabled": true,
    "excludedGlobs": [
      "**/*.html"
    ],
    "respectEslintignore": true,
    "showInStatusBar": false,
    "javascriptScopes": [
      "source.js",
      "source.jsx",
      "source.js.jsx",
      "source.babel",
      "source.js-semantic",
      "text.html.basic",
      "text.html.vue"
    ],
    "typescriptScopes": [
      "source.ts",
      "source.tsx",
      "source.ts.tsx"
    ],
    "cssScopes": [
      "source.css",
      "source.less",
      "source.css.less",
      "source.scss",
      "source.css.scss"
    ],
    "jsonScopes": [
      "source.json"
    ],
    "graphQlScopes": [
      "source.graphql"
    ],
    "whitelistedGlobs": [],
    "isDisabledIfNotInPackageJson": false,
    "isDisabledIfNoConfigFile": false
  },
  "prettierOptions": {
    "parser": "flow",
    "semi": false,
    "singleQuote": false,
    "bracketSpacing": true,
    "useTabs": false,
    "jsxBracketSameLine": false,
    "printWidth": 80,
    "tabWidth": "auto",
    "trailingComma": "none"
  },
  "useEslint": true,
  "useEditorConfig": true,
  "prettierEslintOptions": {
    "prettierLast": false
  }
}

[oltodo]

Installing prettier dependency and restarting Atom both worked for me too :

$ yarn add --dev prettier

If it still not works for you, you also can downgrade prettier-atom to 0.38.0 version using apm :

$ apm install prettier-atom@0.38.0

Finish by relaunching your editor.

[carlos-peru]

thanks a lot @BroFox86 yarn add prettier -D indeed solved the issue!