DRY up formatting padded/aligned columns

[pvdb]

Hey @TylerBrock,

This PR doesn't introduce any functional changes, but rather DRYs up similar, almost identical code that existed in the implementation of the following commands:

• show dbs
• show collections
• count documents

By introducing the printPaddedColumns() helper function, I was able to significantly simplify the implementation of these 3 commands, as the helper provides the formatting of padded/aligned columns, so that the commands only need to implement their respective logic without having to concern themselves about formatting their output.

The printPaddedColumns(keys, values) helper works as follows:

• the so-called "keys" will be right-padded with spaces so that they align to the longest key string, and printed in the left-hand column
• the so-called "values" will be left-padded with spaces so that they align to the longest value string, and printed in the right-hand column
• the two columns will be separated by " → ", but this can be easily changed in config.js

The refactoring isn't completely backwards compatible: the layout of these 3 commands changes slightly, as illustrated by the below before (left) & after (right) screenshot, but arguably the layout is now more consistent and slightly easier to peruse.

Thanks,

@pvdb

[pvdb]

BTW, @TylerBrock, the main driver for this refactor is that implementing the new count collections helper to which I alluded in #133 is now a doddle (so expect another PR shortly after this one gets signed off :smile:):

    if (what == "collections" || what == "tables") {
        databaseNames = db.getMongo().getDatabaseNames();
        collectionCounts = databaseNames.map(function (databaseName) {
            var count = db.getMongo().getDB(databaseName).getCollectionNames().length;
            return (count.commify() + " collection(s)");
        });
        printPaddedColumns(databaseNames, collectionCounts);
        return "";
    }

[TylerBrock]

Cool, thank you! The output of show collections needs some work though. Is there any way we can space things out so the slashes align vertically?

I'm not sure I'm a fan of the arrow. Is that part of standard terminal font sets? I'm running a powerline font so I can't tell anymore what is usual or not :open_mouth:

The benefit for show dbs is marginal. The real advantage is for something like the example you have for count documents so I think this has promise.

[pvdb]

Is there any way we can space things out so the slashes align vertically?

Have a look at 347c2b4 ... that results in:

macpvandenb(mongod-3.0.3) huge> show collections
greasy_spoons  →  645.135MB /  817.719MB
restaurants    → 6872.405MB / 8874.832MB
system.indexes →    0.000MB /    0.008MB
macpvandenb(mongod-3.0.3) huge> _

[pvdb]

I'm not sure I'm a fan of the arrow. Is that part of standard terminal font sets?

The arrow is a UTF-8 character, so won't work in ASCII-only terminals, but then BSON is pretty much UTF-8 so I figured that'd be OK... having said that, though, it's easy enough to change, so maybe I can change it to "-" or some other ASCII separator?

[TylerBrock]

Greatness. Lets merge it in. Thanks for getting back to me so quickly.

[pvdb]

so I think this has promise.

:thumbsup: :smile: