In a lot of our code we have to cast string literals to literals types to conform to types so assignments work:

typeStyles={position:'relative'|'absolute'}letstyles={position:'relative'as'relative'}lets:Styles=styles

This is more common when using React HOCs but above example demonstrate the problem well enough.

With TypeScript 3.4 we'll have theas const literal expression which should be preferred to string or number literal types in this case because changing the value does not require changing the type.

Our example code would be better written as:

typeStyles={position:"relative"|"absolute";};letstyles={position:"relative"asconst};lets:Styles=styles;

More examples:

leta:'str'='str';// badleta=<'str'>'str';// badleta='str'as'str'//badleta='str'asconst// good

// badleto={foo:'string'as'string'}// goodleto={foo:'string'asconst}

Rule name

Please suggest rule name. I'm not sure how this rule should be named

Options

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