Add tslint rules for #3994

[weswigham]

• One variable declaration per variable statement (see Rule to limit variable statements to a single declaration palantir/tslint#525)
• Spaces, not tabs
• No space preceding colons
• Double quotes for strings (though, depending on TSLint's behavior on this, we can be flexible.
• No explicit types for inferrable primitives (can't really use the typesystem on individual files to check for any inference)
• use namespace instead of module (see Add no-internal-module rule palantir/tslint#517)
• else/catch/etc. on a different line (see Complement to [one-line]? palantir/tslint#88)
• Space before { in interfaces, classes, enums, any sort of attached statement body, or type annotation.
• No trailing whitespace
• Forbid boolean/undefined parameters who aren't named.
• Forbid null

[weswigham]

Ping @DanielRosenwasser for some input. (specifically on the inference rule - is it even possible to recover that kind of info from the checker right now?)

[jkillian]

These seem like good rule concepts, any interest in contributing some/all of these directly to TSLint? If not, we'll probably go ahead and add at least some of them ourselves

[weswigham]

I'd probably say to go for it - which ones are you interested in?

[adidahiya]

I'm mainly interested in bringing no-inferrable-types into the core rules.

There seems to be interest in something like next-line as well, but we already have a thread going for that: palantir/tslint#88

[jkillian]

I thought maybe no-null as well? Seems like something people might want

[adidahiya]

I'd like to wait until we see more demand for a no-null-keyword rule -- mainly because I'd like to create another contradictory rule that forbids implicit type casts for null checks (and encourages == null): palantir/tslint#625

[DanielRosenwasser]

Consider TemplateExpression as well

[weswigham]

@DanielRosenwasser feedback integrated.

[DanielRosenwasser]

👍

[weswigham]

@mhegazy would you like to 👍 this?

[mhegazy]

👍

[jkillian]

Just fyi: we're working on adding this to tslint. I've added checking for parameter declarations as well as variable declarations. Feel free to leave feedback if you have any: palantir/tslint#690