ES2015 migration aids

'for..in' is used instead of 'for..of'  

Reports a usage of a for..in loop on an array.

'let' is used instead of 'const'  

Reports a let declaration that can be made const.

'module.exports' is used instead of 'export'  

Reports a module.export statement.

'require()' is used instead of 'import'  

Reports a require() statement.

'var' is used instead of 'let' or 'const'  

Reports a var declaration that is used instead of let or const.

Function expression is used instead of arrow function  

Reports a function expression.

Indexed 'for' is used instead of 'for..of'  

Reports an indexed for loop used on an array.

String concatenation is used instead of template literal  

Reports a string concatenation.