checkvar

checkvar

It checks if a variable is empty or not and returns true (not empty) or false (empty) accordingly. It also can return a CheckResponse type as response, which also includes the variable type.

type CheckResponse = {
    type: CheckType
    result: boolean
}

This module doesn't strictly consider truthy/falsy values, so if you checks 0 or false, you'll get true as result.
Always use the === operator to check for booleans and 0 or 1, use this module just to exclude the "emptiness" of a value.

Definitions of emptiness

This module has the following rules:

• null and undefined are always considered empty, as as such the function will return false.
• number will be false only when the passed value is NaN. 0 will return true instead, as it may be a desired value.
• a function will be considered empty only if it's body is completely empty (comments are stripped away).
• boolean, symbol and bigint will always return true.
• a string will be considered empty if, after having being trimmed, its length is 0.
• an object will be considered empty if its JSON serialization returns {} or '""' (if it was a wrapper for a primitive type like new String()).