How to avoid Flow-type error on an ES7 arrow function

handleSelectCategory = (e) => {
  const { form } = this.state;

  let newCategories = [];
  if (form.categories.findIndex((c) => c.value === e.value) >= 0) {
    newCategories = form.categories.filter((c) => c.value !== e.value);
  } else {
    newCategories = [...form.categories, e];
  }
  this.setState({
    form: Object.assign({}, form, { categories: newCategories }),
  });
};

I receive the warning

Expected parentheses around arrow function argument. (arrow-parens)

How to avoid Flow-type error on an ES7 arrow function

handleSelectCategory = (e) => {
  const { form } = this.state;

  let newCategories = [];
  if (form.categories.findIndex((c) => c.value === e.value) >= 0) {
    newCategories = form.categories.filter((c) => c.value !== e.value);
  } else {
    newCategories = [...form.categories, e];
  }
  this.setState({
    form: Object.assign({}, form, { categories: newCategories }),
  });
};

I receive the warning

Expected parentheses around arrow function argument. (arrow-parens)

• javascript
• reactjs
• eslint

• 6 It's not a type error, it's a linter warning. Have you considered reading its documentation? – Bergi Commented Sep 15, 2018 at 13:49
• same , but i looking for the configuration . my .eslintrc.js 'arrow-parens': ['error', 'as-needed'], on vscode – Yogi Arif Widodo Commented Oct 26, 2022 at 22:43

1 Answer 1

Parentheses around the parameter to an arrow function are optional in ES6 when there's only one argument, but ESLint complains about this by default. This is controlled by the arrow-parens option.

Either change this option, or change your arrow functions to use (c) instead of c as the parameter lists.