Set iD map param with array

[hlfan]

Splitting parameter population and assignment, enabling a singular later default zoom value definition.
A new take on what was dropped in #5597.

[AntonKhorev]

A stylistic change without clear improvements, not even shorter. Adds:

• uninitialized variable
• null value
• magic array index number

[tomhughes]

Thanks for addressing all the review comment - this looks good to me now.

The only thing that slightly confuses me is the need for parentheses around the destructuring on lines 20 and 22 as it seems to work without that when I try it in the node console but eslint does fail to parse it unless you include them!

[hlfan]

MDN says:

The parentheses around the assignment statement are required when using object literal destructuring assignment without a declaration.

As for why it works in the console?
¯\_(ツ)_/¯