BR speed test for rudimentary versions

Join an array of strings into one string.

Apply a function to each key-value pair in the source object, then join the results into a string.

Make a new object by applying a function to each value of the source object.

Comparing string concatenation (+) vs concat method.

https://www.measurethat.net/Benchmarks/Show/12770/0/delete-vs-null, but with Maps

Compares slice, substr and substring to each other when there is only a start index

which is faster to check for zero

Comparing performance of: Array#push vs Array#apply

aaa