TypeScript ESLint JSX Conditionals

TypeScript ESLint rule to remove unsafe conditionals in JSX.

npm install --save-dev eslint-plugin-typescript-eslint-jsx-conditionals yarn add -D eslint-plugin-typescript-eslint-jsx-conditionals

.eslintrc.js example:

module.exports = {
  root: true,
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint', 'typescript-eslint-jsx-conditionals'],
  ignorePatterns: ['.eslintrc.js'],
  rules: {
    'typescript-eslint-jsx-conditionals/strict-jsx-conditionals': 'error',
  },
}

Valid:

const Component = ({ check }: { check: boolean }) => {
  return <div>{check && <p>Check</p>}</div>
}

const HelloWorld = () => {
  const someCondition = true
  return <div>{someCondition && <p>Check</p>}</div>
}

Invalid:

Check might be undefined.

const Component = ({ check }: { check?: boolean }) => {
  return <div>{check && <p>Check</p>}</div>
}

message.length is a number

const HelloWorld = () => {
  const message = 'hello world'

  return <div>{message.length && <p>Check</p>}</div>
}

Check might not be a boolean

const Component = ({ check }: { check: boolean | string | null }) => {
  return <div>{check && <p>Check</p>}</div>
}

Options

Name	Type	Default Value	Description
preferBoolean	boolean	false	When using auto-fix, use Boolean() cast instead of !!
normalize	boolean	false	ensure that your whole codebase uses the same type of casting - HIGHLY EXPERIMENTAL and NOT recommended