react-navigation/src/routers/validateScreenOptions.js

Routing and navigation for your React Native apps

const deprecatedKeys = ['tabBar'];

/**
 * Make sure screen options returned by the `getScreenOption`
 * are valid
 */
export default (screenOptions, route) => {
  const keys = Object.keys(screenOptions);

  const deprecatedKey = keys.find(key => deprecatedKeys.includes(key));

  if (typeof screenOptions.title === 'function') {
    throw new Error(
      [
        `\`title\` cannot be defined as a function in navigation options for \`${
          route.routeName
        }\` screen. \n`,
        'Try replacing the following:',
        '{',
        '    title: ({ state }) => state...',
        '}',
        '',
        'with:',
        '({ navigation }) => ({',
        '    title: navigation.state...',
        '})',
      ].join('\n')
    );
  }

  if (deprecatedKey && typeof screenOptions[deprecatedKey] === 'function') {
    throw new Error(
      [
        `\`${deprecatedKey}\` cannot be defined as a function in navigation options for \`${
          route.routeName
        }\` screen. \n`,
        'Try replacing the following:',
        '{',
        `    ${deprecatedKey}: ({ state }) => ({`,
        '         key: state...',
        '    })',
        '}',
        '',
        'with:',
        '({ navigation }) => ({',
        `    ${deprecatedKey}Key: navigation.state...`,
        '})',
      ].join('\n')
    );
  }

  if (deprecatedKey && typeof screenOptions[deprecatedKey] === 'object') {
    throw new Error(
      [
        `Invalid key \`${deprecatedKey}\` defined in navigation options for \`${
          route.routeName
        }\` screen.`,
        '\n',
        'Try replacing the following navigation options:',
        '{',
        `    ${deprecatedKey}: {`,
        ...Object.keys(screenOptions[deprecatedKey]).map(
          key => `        ${key}: ...,`
        ),
        '    },',
        '}',
        '\n',
        'with:',
        '{',
        ...Object.keys(screenOptions[deprecatedKey]).map(
          key =>
            `    ${deprecatedKey + key[0].toUpperCase() + key.slice(1)}: ...,`
        ),
        '}',
      ].join('\n')
    );
  }
};