Rosetta Code: Count the coins

[JeremyLT]

FCC’s environment uses ‘strict mode’ by default:

JavaScript Strict Mode Explained with Examples

Strict Mode was introduced in ECMAScript 5 that allows you to place a program, or a function, in a “strict” operating context. This strict context prevents certain actions from being taken and throws more exceptions. Strict mode makes several changes to normal JavaScript semantics. First, strict mode eliminates some JavaScript silent errors by changing them to throw errors. Second, strict mode fixes mistakes that make it difficult for JavaScript engines to perform optimizations: strict mode c…